Bibliography database of Radiophysics Laboratory (RpLab) -- Query Results

	Bibliography database of Radiophysics Laboratory (RpLab) Home \| Show All \| Simple Search \| Advanced Search	Login Quick Search: Field: contains: ...
	401-500 of 891 records found matching your query:

Search & Display Options

Select All Deselect All

<< 1 2 3 4 5 6 7 8 9 >>

List View

Citations

Details

	Records
	Author	Sidorova, M.; Semenov, A.; Korneev, A.; Chulkova, G.; Korneeva, Y.; Mikhailov, M.; Devizenko, A.; Kozorezov, A.; Goltsman, G.
	Title	Electron-phonon relaxation time in ultrathin tungsten silicon film			Type	Miscellaneous
	Year	2018	Publication	arXiv	Abbreviated Journal
	Volume		Issue		Pages
	Keywords	WSi film
	Abstract	Using amplitude-modulated absorption of sub-THz radiation (AMAR) method, we studied electron-phonon relaxation in thin disordered films of tungsten silicide. We found a response time ~ 800 ps at critical temperature Tc = 3.4 K, which scales as minus 3 in the temperature range from 1.8 to 3.4 K. We discuss mechanisms, which can result in a strong phonon bottle-neck effect in a few nanometers thick film and yield a substantial difference between the measured time, characterizing response at modulation frequency, and the inelastic electron-phonon relaxation time. We estimate the electron-phonon relaxation time to be in the range ~ 100-200 ps at 3.4 K.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes	Duplicated as 1341			Approved	no
	Call Number				Serial	1340
Permanent link to this record



	Author	Sidorova, M. V.; Kozorezov, A. G.; Semenov, A. V.; Korneev, A. A.; Chulkova, G. M.; Korneeva, Y. P.; Mikhailov, M. Y.; Devizenko, A. Y.; Goltsman, G. N.
	Title	Non-bolometric bottleneck in electron-phonon relaxation in ultra-thin WSi film			Type	Miscellaneous
	Year	2018	Publication	arXiv	Abbreviated Journal
	Volume		Issue		Pages
	Keywords	WSi films, diffusion constant, SSPD, SNSPD
	Abstract	We developed the model of the internal phonon bottleneck to describe the energy exchange between the acoustically soft ultrathin metal film and acoustically rigid substrate. Discriminating phonons in the film into two groups, escaping and nonescaping, we show that electrons and nonescaping phonons may form a unified subsystem, which is cooled down only due to interactions with escaping phonons, either due to direct phonon conversion or indirect sequential interaction with an electronic system. Using an amplitude-modulated absorption of the sub-THz radiation technique, we studied electron-phonon relaxation in ultrathin disordered films of tungsten silicide. We found an experimental proof of the internal phonon bottleneck. The experiment and simulation based on the proposed model agree well, resulting in tau{e-ph} = 140-190 ps at TC = 3.4 K, supporting the results of earlier measurements by independent techniques.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes	Duplicated as 1305			Approved	no
	Call Number				Serial	1341
Permanent link to this record



	Author	Kurochkin, V. L.; Zverev, A. V.; Kurochkin, Y. V.; Ryabtsev, I. I.; Neizvestnyi, I. G.; Ozhegov, R. V.; Gol’tsman, G. N.; Larionov, P. A.
	Title	Long-distance fiber-optic quantum key distribution using superconducting detectors			Type	Conference Article
	Year	2015	Publication	Proc. Optoelectron. Instrum.	Abbreviated Journal	Proc. Optoelectron. Instrum.
	Volume	51	Issue	6	Pages	548-552
	Keywords	QKD, SSPD, SNSPD
	Abstract	This paper presents the results of experimental studies on quantum key distribution in optical fiber using superconducting detectors. Key generation was obtained on an experimental setup based on a self-compensation optical circuit with an optical fiber length of 101.1 km. It was first shown that photon polarization encoding can be used for quantum key distribution in optical fiber over a distance in excess of 300 km.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	8756-6990	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1342
Permanent link to this record



	Author	Vodolazov, D. Y.; Korneeva, Y. P.; Semenov, A. V.; Korneev, A. A.; Goltsman, G. N.
	Title	Vortex-assisted mechanism of photon counting in a superconducting nanowire single-photon detector revealed by external magnetic field			Type	Journal Article
	Year	2015	Publication	Phys. Rev. B	Abbreviated Journal	Phys. Rev. B
	Volume	92	Issue	10	Pages	104503 (1 to 9)
	Keywords	SSPD, SNSPD
	Abstract	We use an external magnetic field to probe the detection mechanism of a superconducting nanowire single-photon detector. We argue that the hot belt model (which assumes partial suppression of the superconducting order parameter Δ across the whole width of the superconducting nanowire after absorption of the photon) does not explain observed weak-field dependence of the photon count rate (PCR) for photons with λ=450nm and noticeable decrease of PCR (with increasing the magnetic field) in a range of the currents for photons with wavelengths λ=450–1200nm. Found experimental results for all studied wavelengths can be explained by the vortex hot spot model (which assumes partial suppression of Δ in the area with size smaller than the width of the nanowire) if one takes into account nucleation and entrance of the vortices to the photon induced hot spot and their pinning by the hot spot with relatively large size and strongly suppressed Δ.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1098-0121	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1343
Permanent link to this record



	Author	Murphy, A.; Semenov, A.; Korneev, A.; Korneeva, Y.; Gol'tsman, G.; Bezryadin, A.
	Title	Three temperature regimes in superconducting photon detectors: quantum, thermal and multiple phase-slips as generators of dark counts			Type	Journal Article
	Year	2015	Publication	Sci. Rep.	Abbreviated Journal	Sci. Rep.
	Volume	5	Issue		Pages	10174 (1 to 10)
	Keywords	SPD, SSPD, SNSPD
	Abstract	We perform measurements of the switching current distributions of three w approximately 120 nm wide, 4 nm thick NbN superconducting strips which are used for single-photon detectors. These strips are much wider than the diameter of the vortex cores, so they are classified as quasi-two-dimensional (quasi-2D). We discover evidence of macroscopic quantum tunneling by observing the saturation of the standard deviation of the switching distributions at temperatures around 2 K. We analyze our results using the Kurkijarvi-Garg model and find that the escape temperature also saturates at low temperatures, confirming that at sufficiently low temperatures, macroscopic quantum tunneling is possible in quasi-2D strips and can contribute to dark counts observed in single photon detectors. At the highest temperatures the system enters a multiple phase-slip regime. In this range single phase-slips are unable to produce dark counts and the fluctuations in the switching current are reduced.
	Address	Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2045-2322	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:25988591; PMCID:PMC4437302			Approved	no
	Call Number				Serial	1344
Permanent link to this record



	Author	Beck, M.; Klammer, M.; Rousseau, I.; Gol’tsman, G. N.; Diamant, I.; Dagan, Y.; Demsar, J.
	Title	Probing superconducting gap dynamics with THz pulses			Type	Conference Article
	Year	2015	Publication	CLEO	Abbreviated Journal	CLEO
	Volume		Issue		Pages	SM3H.3 (1 to 2)
	Keywords	superconducting gap; electric fields; femtosecond pulses; near infrared radiation; picosecond pulses; superconductors; thin films
	Abstract	We studied superconducting gap dynamics in a BCS superconductor NbN and electron doped cuprate superconductor PCCO following excitation with near-infrared (NIR) and narrow band THz pulses. Systematic studies on PCCO imply very selective electron-phonon coupling.
	Address
	Corporate Author				Thesis
	Publisher	Optical Society of America	Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1345
Permanent link to this record



	Author	Galin, M. A.; Klushin, A. M.; Kurin, V. V.; Seliverstov, S. V.; Finkel, M. I.; Goltsman, G. N.; Müller, F.; Scheller, T.; Semenov, A. D.
	Title	Towards local oscillators based on arrays of niobium Josephson junctions			Type	Journal Article
	Year	2015	Publication	Supercond. Sci. Technol.	Abbreviated Journal	Supercond. Sci. Technol.
	Volume	28	Issue	5	Pages	055002 (1 to 7)
	Keywords	Josephson junction local oscillators, JJ LO
	Abstract	Various applications in the field of terahertz technology are in urgent need of compact, wide-tunable solid-state continuous wave radiation sources with a moderate power. However, satisfactory solutions for the THz frequency range are scarce yet. Here we report on coherent radiation from a large planar array of Josephson junctions (JJs) in the frequency range between 0.1 and 0.3 THz. The external resonator providing the synchronization of JJ array is identified as a straight fragment of a single-strip-line containing the junctions themselves. We demonstrate a prototype of the quasioptical heterodyne receiver with the JJ array as a local oscillator and a hot-electron bolometer mixer.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0953-2048	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1347
Permanent link to this record



	Author	Korneeva, Y.; Sidorova, M.; Semenov, A.; Krasnosvobodtsev, S.; Mitsen, K.; Korneev, A.; Chulkova, G.; Goltsman, G.
	Title	Comparison of hot-spot formation in NbC and NbN single-photon detectors			Type	Journal Article
	Year	2016	Publication	IEEE Trans. Appl. Supercond.	Abbreviated Journal	IEEE Trans. Appl. Supercond.
	Volume	26	Issue	3	Pages	1-4
	Keywords	NbC, NbN SSPD, SNSPD
	Abstract	We report an experimental investigation of the hot-spot evolution in superconducting single-photon detectors made of disordered superconducting materials with different diffusivity and energy downconversion time values, i.e., 33-nm-thick NbN and 23-nm-thick NbC films. We have demonstrated that, in NbC film, only 405-nm photons produce sufficiently large hot spot to trigger a single-photon response. The dependence of detection efficiency on bias current for 405-nm photons in NbC is similar to that for 3400-nm photons in NbN. In NbC, large diffusivity and downconversion time result in 1-D critical current suppression profile compared with the usual 2-D profile in NbN.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1051-8223	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1348
Permanent link to this record



	Author	Goltsman, G. N.; Samartsev, V. V.; Vinogradov, E. A.; Naumov, A. V.; Karimullin, K. R.
	Title	New generation of superconducting nanowire single-photon detectors			Type	Conference Article
	Year	2015	Publication	EPJ Web of Conferences	Abbreviated Journal	EPJ Web of Conferences
	Volume	103	Issue		Pages	01006 (1 to 2)
	Keywords	SSPD, SNSPD
	Abstract	We present an overview of recent results for new generation of infrared and optical superconducting nanowire single-photon detectors (SNSPDs) that has already demonstrated a performance that makes them devices-of-choice for many applications. SNSPDs provide high efficiency for detecting individual photons while keeping dark counts and timing jitter minimal. Besides superior detection performance over a broad optical bandwidth, SNSPDs are also compatible with an integrated optical platform as a crucial requirement for applications in emerging quantum photonic technologies. By embedding SNSPDs in nanophotonic circuits we realize waveguide integrated single photon detectors which unite all desirable detector properties in a single device.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2100-014X	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1349
Permanent link to this record



	Author	Fedorov, G. E.; Gaiduchenko, I. A.; Golikov, A. D.; Rybin, M. G.; Obraztsova, E. D.; Voronov, B. M.; Coquillat, D.; Diakonova, N.; Knap, W.; Goltsman, G. N.; Samartsev, V. V.; Vinogradov, E. A.; Naumov, A. V.; Karimullin, K. R.
	Title	Response of graphene based gated nanodevices exposed to THz radiation			Type	Conference Article
	Year	2015	Publication	EPJ Web of Conferences	Abbreviated Journal	EPJ Web of Conferences
	Volume	103	Issue		Pages	10003 (1 to 2)
	Keywords	graphene field-effect transistor, FET
	Abstract	In this work we report on the response of asymmetric graphene based devices to subterahertz and terahertz radiation. Our devices are made in a configuration of a field-effect transistor with conduction channel between the source and drain electrodes formed with a CVD-grown graphene. The radiation is coupled through a spiral antenna to source and top gate electrodes. Room temperature responsivity of our devices is close to the values that are attractive for commercial applications. Further optimization of the device configuration may result in appearance of novel terahertz radiation detectors.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2100-014X	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1350
Permanent link to this record



	Author	Florya, I. N.; Korneeva, Y. P.; Sidorova, M. V.; Golikov, A. D.; Gaiduchenko, I. A.; Fedorov, G. E.; Korneev, A. A.; Voronov, B. M.; Goltsman, G. N.; Samartsev, V. V.; Vinogradov, E. A.; Naumov, A. V.; Karimullin, K. R.
	Title	Energy relaxtation and hot spot formation in superconducting single photon detectors SSPDs			Type	Conference Article
	Year	2015	Publication	EPJ Web of Conferences	Abbreviated Journal	EPJ Web of Conferences
	Volume	103	Issue		Pages	10004 (1 to 2)
	Keywords	SSPD, SNSPD
	Abstract	We have studied the mechanism of energy relaxation and resistive state formation after absorption of a single photon for different wavelengths and materials of single photon detectors. Our results are in good agreement with the hot spot model.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2100-014X	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1351
Permanent link to this record



	Author	Elezov, M. S.; Ozhegov, R. V.; Kurochkin, Y. V.; Goltsman, G. N.; Makarov, V. S.; Samartsev, V. V.; Vinogradov, E. A.; Naumov, A. V.; Karimullin, K. R.
	Title	Countermeasures against blinding attack on superconducting nanowire detectors for QKD			Type	Conference Article
	Year	2015	Publication	EPJ Web Conf.	Abbreviated Journal	EPJ Web Conf.
	Volume	103	Issue		Pages	10002 (1 to 2)
	Keywords	SSPD, SNSPD, QKD
	Abstract	Nowadays, the superconducting single-photon detectors (SSPDs) are used in Quantum Key Distribution (QKD) instead of single-photon avalanche photodiodes. Recently bright-light control of the SSPD has been demonstrated. This attack employed a “backdoor” in the detector biasing technique. We developed the autoreset system which returns the SSPD to superconducting state when it is latched. We investigate latched state of the SSPD and define limit conditions for effective blinding attack. Peculiarity of the blinding attack is a long nonsingle photon response of the SSPD. It is much longer than usual single photon response. Besides, we need follow up response duration of the SSPD. These countermeasures allow us to prevent blind attack on SSPDs for Quantum Key Distribution.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2100-014X	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1352
Permanent link to this record



	Author	Mehdi, I.; Gol'tsman, G.; Putz, P.
	Title	Introduction to the mini-special-issue on the 25th international symposium on space terahertz technology (ISSTT)			Type	Miscellaneous
	Year	2015	Publication	IEEE Trans. THz Sci. Technol.	Abbreviated Journal	IEEE Trans. THz Sci. Technol.
	Volume	5	Issue	1	Pages	14-15
	Keywords
	Abstract	THE 25th International Symposium on Space Terahertz Technology (ISSTT) was held in Moscow, Russia, between April 27–30, 2014. The conference was organized by Moscow State Pedagogical University and the Higher School of Economics (National Research University) and Chaired by Professor Gregory Gol'tsman of Moscow State Pedagogical University. The conference was attended by roughly 150 participants from 15 countries. The technology covered by ISSTT includes detectors, devices, circuits and systems in various areas of THz science and technology. Each year this symposium brings together the global THz space science technology community, and as such, emphasizes the broad international collaboration that is required to execute these large complicated instrument programs that dominate this field. However, talks covering technologies for balloon, aircraft, and ground-based telescopes were also presented. In this special section of IEEE Transactions on Terahertz Science and Technology, we include eight expanded papers from the 25th ISSTT symposium. The papers range from development of SIS mixers to optical adjustment systems for radio telescopes. The 26th ISSTT will be held in Boston, MA, USA, during March 16–18, 2015. Researchers and scientist involved in THz research are invited to attend this symposium (more details are at http://www.cfa.harvard.edu/events/2015/isstt2015/). You can access the full list of papers presented at the ISSTT symposia from the National Radio Astronomy Observatory website: http://www.nrao.edu/meetings/isstt/index.shtml Yours sincerely
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2156-342X	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1353
Permanent link to this record



	Author	Tong, C.-Y. E.; Trifonov, A.; Shurakov, A.; Blundell, R.; Gol’tsman, G.
	Title	A microwave-operated hot-electron-bolometric power detector for terahertz radiation			Type	Journal Article
	Year	2015	Publication	IEEE Trans. Appl. Supercond.	Abbreviated Journal	IEEE Trans. Appl. Supercond.
	Volume	25	Issue	3	Pages	2300604 (1 to 4)
	Keywords	NbN HEB mixer
	Abstract	A new class of microwave-operated THz power detectors based on the NbN hot-electron-bolometer (HEB) mixer is proposed. The injected microwave signal ( 1 GHz) serves the dual purpose of pumping the HEB element and enabling the read-out of the internal state of the device. A cryogenic amplifier amplifies the reflected microwave signal from the device and a homodyne scheme recovers the effects of the incident THz radiation. Two modes of operation have been identified, depending on the level of incident radiation. For weak signals, we use a chopper to chop the incident radiation against a black body reference and a lock-in amplifier to perform synchronous detection of the homodyne readout. The voltage measured is proportional to the incident power, and we estimate an optical noise equivalent power of 5pW/ √Hz at 0.83 THz. At higher signal levels, the homodyne circuit recovers the stream of steady relaxation oscillation pulses from the HEB device. The frequency of these pulses is in the MHz frequency range and bears a linear relationship with the incident THz radiation over an input power range of 15 dB. A digital frequency counter is used to measure THz power. The applicable power range is between 1 nW and 1 μW.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1558-2515	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1354
Permanent link to this record



	Author	Trifonov, A.; Tong, C.-Y. E.; Blundell, R.; Ryabchun, S.; Gol'tsman, G.
	Title	Probing the stability of HEB mixers with microwave injection			Type	Journal Article
	Year	2015	Publication	IEEE Trans. Appl. Supercond.	Abbreviated Journal	IEEE Trans. Appl. Supercond.
	Volume	25	Issue	3	Pages	2300404 (1 to 4)
	Keywords	NbN HEB mixer, stability, Allan-variance
	Abstract	Using a microwave probe as a tool, we have performed experiments aimed at understanding the origin of the output-power fluctuations in hot-electron-bolometer (HEB) mixers. We use a probe frequency of 1.5 GHz. The microwave probe picks up impedance changes of the HEB, which are examined upon demodulation of the reflected wave outside the cryostat. This study shows that the HEB mixer operates in two different regimes under a terahertz pump. At a low pumping level, strong pulse modulation is observed, as the device switches between the superconducting state and the normal state at a rate of a few megahertz. When pumped much harder, to approximate the low-noise mixer operating point, residual modulation can still be observed, showing that the HEB mixer is intrinsically unstable even in the resistive state. Based on these observations, we introduced a low-frequency termination to the HEB mixer. By terminating the device in a 50-Ω resistor in the megahertz frequency range, we have been able to improve the output-power Allan time of our HEB receiver by a factor of four to about 10 s for a detection bandwidth of 15 MHz, with a corresponding gain fluctuation of about 0.035%.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1051-8223	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1355
Permanent link to this record



	Author	Murphy, A.; Semenov, A.; Korneev, A.; Korneeva, Y.; Gol’tsman, G.; Bezryadin, A.
	Title	Dark counts initiated by macroscopic quantum tunneling in NbN superconducting photon detectors			Type	Miscellaneous
	Year	2014	Publication	arXiv	Abbreviated Journal
	Volume		Issue		Pages
	Keywords	NbN SSPD
	Abstract	We perform measurements of the switching current distributions of three w = 120 nm wide, 4 nm thick NbN superconducting strips which are used for single-photon detectors. These strips are much wider than the diameter the vortex cores, so they are classified as quasi-two-dimensional (quasi-2D). We discover evidence of macroscopic quantum tunneling by observing the saturation of the standard deviation of the switching distributions at temperatures around 2 K. We analyze our results using the Kurkijarvi-Garg model and find that the escape temperature also saturates at low temperatures, confirming that at sufficiently low temperatures, macroscopic quantum tunneling is possible in quasi-2D strips and can contribute to dark counts observed in single photon detectors.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number	murphy2014dark			Serial	1356
Permanent link to this record



	Author	Lusche, R.; Semenov, A.; Ilin, K.; Siegel, M.; Korneeva, Y.; Trifonov, A.; Korneev, A.; Goltsman, G.; Vodolazov, D.; Hübers, H.-W.
	Title	Effect of the wire width on the intrinsic detection efficiency of superconducting-nanowire single-photon detectors			Type	Journal Article
	Year	2014	Publication	J. Appl. Phys.	Abbreviated Journal	J. Appl. Phys.
	Volume	116	Issue	4	Pages	043906 (1 to 9)
	Keywords	NbN SSPD, SNSPD, TaN
	Abstract	A thorough spectral study of the intrinsic single-photon detection efficiency in superconducting TaN and NbN nanowires with different widths has been performed. The experiment shows that the cut-off of the intrinsic detection efficiency at near-infrared wavelengths is most likely controlled by the local suppression of the barrier for vortex nucleation around the absorption site. Beyond the cut-off quasi-particle diffusion in combination with spontaneous, thermally activated vortex crossing explains the detection process. For both materials, the reciprocal cut-off wavelength scales linearly with the wire width where the scaling factor agrees with the hot-spot detection model.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0021-8979	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1357
Permanent link to this record



	Author	Zhang, W.; Miao, W.; Zhong, J. Q.; Shi, S. C.; Hayton, D. J.; Vercruyssen, N.; Gao, J. R.; Goltsman, G. N.
	Title	Temperature dependence of the receiver noise temperature and IF bandwidth of superconducting hot electron bolometer mixers			Type	Journal Article
	Year	2014	Publication	Supercond. Sci. Technol.	Abbreviated Journal	Supercond. Sci. Technol.
	Volume	27	Issue	8	Pages	085013 (1 to 5)
	Keywords	NbN HEB mixers
	Abstract	In this paper we study the temperature dependence of the receiver noise temperature and IF noise bandwidth of superconducting hot electron bolometer (HEB) mixers. Three superconducting NbN HEB devices of different transition temperatures (Tc) are measured at 0.85 THz and 1.4 THz at different bath temperatures (Tbath) between 4 K and 9 K. Measurement results demonstrate that the receiver noise temperature of superconducting NbN HEB devices is nearly constant for Tbath/Tc, less than 0.8, which is consistent with the simulation based on a distributed hot-spot model. In addition, the IF noise bandwidth appears independent of Tbath/Tc, indicating the dominance of phonon cooling in the investigated HEB devices.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0953-2048	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1358
Permanent link to this record



	Author	Semenov, A.; Richter, H.; Hübers, H.-W.; Petrenko, D.; Tretyakov, I.; Ryabchun, S.; Finkel, M.; Kaurova, N.; Gol’tsman, G.; Risacher, C.; Ricken, O.; Güsten, R.
	Title	Optimization of the intermediate frequency bandwidth in the THz HEB mixers			Type	Abstract
	Year	2014	Publication	Proc. 25^th Int. Symp. Space Terahertz Technol.	Abbreviated Journal	Proc. 25^th Int. Symp. Space Terahertz Technol.
	Volume		Issue		Pages	54
	Keywords	NbN HEB mixer
	Abstract	We report on the studies of the intermediate frequency (IF) bandwidth of quasi-optically coupled NbN hot-electron bolometer (HEB) mixers which are aimed at the optimization of the mixer performance at terahertz frequencies. Extension of the IF bandwidth due to the contribution of electron diffusion to the heat removal from NbN microbolometers has been already demonstrated for NbN HEBs at subterahertz frequencies. However, reducing the size of the microbolometer causes degradation of the noise temperature. Using in-situ multilayer manufacturing process we succeeded to improve the transparency of the contacts for electrons which go away from microbolometer to the metallic antenna. The improved transparency and hence coupling efficiency counterbalances the noise temperature degradation. HEB mixers were tested in a laboratory heterodyne receiver with a narrow-band cold filter which allowed us to eliminate direct detection. We used a local oscillator with a quantum cascade laser (QCL) at a frequency of 4.745 THz [1] which was developed for the H-Channel of the German Receiver for Astronomy at Terahertz frequencies (GREAT). Both the noise and gain bandwidth were measured in the IF range from 0.5 to 8 GHz using the hot-cold technique and preliminary calibrated IF analyzer with a tunable microwave filter. For optimized HEB geometry we found the noise bandwidth as large as 7 GHz. We compare our results with the conventional and the hot-spot mixer models and show that further extension of the IF bandwidth should be possible via improving the sharpness of the superconducting transition. The cross characterization of the HEB mixer was performed in the test bed of GREAT at the Max-Planck-Institut für Radioastronomie with the same QCL LO and delivered results which were consistent with the laboratory studies.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1359
Permanent link to this record



	Author	Fedorov, G.; Kardakova, A.; Gayduchenko, I.; Voronov, B. M.; Finkel, M.; Klapwijk, T. M.; Goltsman, G.
	Title	Photothermoelectric response in asymmetric carbon nanotube devices exposed to sub-THz radiation			Type	Abstract
	Year	2014	Publication	Proc. 25^th Int. Symp. Space Terahertz Technol.	Abbreviated Journal	Proc. 25^th Int. Symp. Space Terahertz Technol.
	Volume		Issue		Pages	71
	Keywords	carbon nanotubes, CNT
	Abstract	This work reports on the voltage response of asymmetric carbon nanotube devices to sub-THz radiation at the frequency of 140 GHz. The devices contain CNT’s, which are over their length partially suspended and partially Van der Waals bonded to a SiO 2 substrate, causing a difference in thermal contact. Different heat sinking of CNTs by source and drain gives rise to temperature gradient and consequent thermoelectric power (TEP) as such a device is exposed to the sub-THz radiation. Sign of the DC signal, its power and gate voltage dependence observed at room temperature are consistent with this scenario. At liquid helium temperature the observed response is more complex. DC voltage signal of an opposite sign is observed in a narrow range of gate voltages at low temperatures and under low radiation power. We argue that this may indicate a true photovoltaic response from small gap (less than 10meV) CNT’s, an effect never reported before. While it is not clear if the observed effects can be used to develop efficient THz detectors we note that the responsivity of our devices exceeds that of CNT based devices in microwave or THz range reported before at room temperature. Besides at 4.2 K notable increase of the sample conductance (at least four-fold) is observed. Our recent results with asymmetric carbon nanotube devices response to THz radiation (2.5 THz) will also be presented.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1361
Permanent link to this record



	Author	Tretyakov, Ivan; Seliverstov, Sergey; Zolotov, Philipp; Kaurova, Natalya; Voronov, Boris; Finkel, Matvey; Goltsman, Gregory
	Title	Noise temperature and noise bandwidth of hot-electron bolometer mixer at 3.8 THz			Type	Abstract
	Year	2014	Publication	Proc. 25^th Int. Symp. Space Terahertz Technol.	Abbreviated Journal	Proc. 25^th Int. Symp. Space Terahertz Technol.
	Volume		Issue		Pages	77
	Keywords	NbN HEB mixer
	Abstract	We report on our recent results of double sideband (DSB) noise temperature and bandwidth measurements of quasi-optical hot electron bolometer (HEB) mixers at local oscillator frequency of 3.8 THz. The HEB mixers used in this work were made of a NbN thin film and had a superconducting transition temperature of about 10.3 K. To couple terahertz radiation, the NbN microbridge (0.2 μm long and 2 μm wide) was integrated with a planar logarithmic-spiral antenna. The mixer chip was glued to an elliptical Si lens clamped tightly to a mixer block mounted on the 4.2 K plate of a liquid helium cryostat. The terahertz radiation was fed into the HEB device through the cryostat window made of a 0.5 mm thick HDPE. A band-pass mesh filter was mounted on the 4.2 K plate to minimize the direct detection effect [1]. We used a gas discharge laser irradiating at 3.8 THz H 2 0 line as a local oscillator (LO). The LO power was combined with a black body broadband radiation via Mylar beam splitter. Our receiver allows heterodyne detection with an intermediate frequency (IF) of a several gigahertz which dictates usage of a wideband SiGe low noise amplifier [2]. The receiver IF output signal was further amplified at room temperature and fed into a square-law power detector through a band-pass filter. The DSB receiver noise temperature was measured using a conventional Y-factor technique at IF of 1.25 GHz and band of 40 MHz. Using wideband amplifiers at both cryogenic and room temperature stages we have estimated IF bandwidth of the HEB mixers used. The obtained results strengthen the position of the HEB mixer as one of the most important tools for submillimeter astronomy. This device operates well above the energy gap (at frequencies above 1 THz) where performance of state-of-the-art SIS mixers starts to degrade. So, HEB mixers are expected to be a device of choice in astrophysical observations (ground-, aircraft- and space-based) at THz frequencies due to its excellent noise performance and low LO power requirements. The HEB mixers will be in operation on Millimetron Space Observatory. References 1. J. J. A. Baselmans, A. Baryshev, S. F. Reker, M. Hajenius, J. R. Gao, T. M. Klapwijk, Yu. Vachtomin, S. Maslennikov, S. Antipov, B. Voronov, and G. Gol'tsman, Appl. Phys. Lett., 86, 163503 (2005). 2. Sander Weinreb, Life Fellow, IEEE, Joseph C. Bardin, Student Member, IEEE, and Hamdi Mani, “Design of Cryogenic SiGe Low-Noise Amplifiers”, IEEE Transactions on Microwave Theory and Techniques, 55, 11, 2007.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1362
Permanent link to this record



	Author	Kinev, N. V.; Filippenko, L. V.; Ozhegov, R. V.; Gorshkov, K. N.; Gol’tsman, G. N.; Koshelets, V. P.
	Title	Superconducting integrated receiver with HEB-mixer			Type	Abstract
	Year	2014	Publication	Proc. 25^th Int. Symp. Space Terahertz Technol.	Abbreviated Journal	Proc. 25^th Int. Symp. Space Terahertz Technol.
	Volume		Issue		Pages	78
	Keywords	NbN HEB mixer, SIR, superconducting integrated receiver
	Abstract	Detectors in THz range with high sensitivity are very essential nowadays in different fields: space technology, atmospheric research, medicine and security. The most sensitive heterodyne detectors below 1 THz are the SIS- mixers due to its extremely high non-linearity and low noise level. Nevertheless, their effective range is strongly limited by superconducting gap Δ (about 1 THz for NbN circuits). Above 1 THz the detectors based on HEB (hot electron bolometers) are more effective [1]; their operation frequency is not limited from above and can be up to 70 THz [2]. HEBs can perform as both direct and heterodyne detectors (mixers). All HEB-mixers are used with external heterodyne, most useful are synthesizer with multipliers, quantum cascade lasers or far infrared lasers and backward-wave oscillators. Superconducting integrated receiver (SIR) is based on implementation of both SIS-miser and flux flow oscillator (FFO) acting as heterodyne at single chip [3]. Such receiver has been successfully applied at TELIS balloon-borne instrument for study of atmospheric constituents [4] and looks as very promising device for other THz missions including space research. Thus, there is a task to expand its operating range to higher frequencies. The frequency range of the SIR the operation is limited by both the SIS-mixer and the FFO maximum frequencies. The idea of present work is implementation of the HEB as a mixer in the SIR instead of the SIS traditionally used. We introduce the first results of integrating the HEB-mixer coupled to planar slot antenna with the FFO on one chip. For properly FFO operation the SIS harmonic mixer is used to phase lock the oscillator. The scheme of the SIR based on the HEB- mixer is presented in fig. 1. We have demonstrated the principal possibility of integration of both the HEB-mixer and the flux-flow oscillator on a single chip and succeed with sufficient power coupling for properly receiver operation. We measured the direct response of the HEB coupled to the antenna at THz frequencies by the FTS setup and noise temperature of the receiver with standard Y- factor measuring technique. The SIR operating range 450-620 GHz was achieved with the best uncorrected noise temperature of about 1000 К. One should note that it is still quite low frequencies for effective operation of the HEB-mixer; therefore we expect to obtain the better results for frequencies above 700 GHz (up to 1.2 THz). Another additional task is to increase the FFO frequencies by using NbTiN electrodes instead of NbN; currently we are working on this issue. This work was supported by the RFBR grant, the Ministry of Education and Science of Russia and Russian Academy of Sciences. References 1. D. Semenov, H.-W. Hubers, J. Schubert, G. N. Gol’tsman, A. I. Elantiev, B. M. Voronov, E. M. Gershenzon, Design and performance of the lattice-cooled hot-electron terahertz mixer, J. Appl. Phys. 88, 6758, 2000. 2. Maslennikov S. N., Finkel M. I., Antipov S. V. et al. Spiral antenna coupled and directly coupled NbN HEB mixers in the frequency range from 1 to 70THz. Proc. 17 th international symposium on space terahertz technology. Paris, France: 2006.—may. Pp. 177 – 179. 3. V.P. Koshelets, S.V. Shitov. Integrated Superconducting Receivers. Supercond. Sci. Technol. Vol. 13. P. R53-R59. 2000. 4. Gert de Lange, Dick Boersma, Johannes Dercksen et.al. Development and Characterization of the Superconducting Integrated Receiver Channel of the TELIS Atmospheric Sounder. Supercond. Sci. Technol. vol. 23, No 4, 045016 (8pp). 2010.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1363
Permanent link to this record



	Author	Shcherbatenko, Michael; Lobanov, Yury; Finkel, Matvey; Maslennikov, Sergey; Pentin, Ivan; Semenov, Alexander; Titova, Nadezhda; Kaurova, Natalya; Voronov, Boris M.; Rodin, Alexander; Klapwijk, Teunis M.; Gol’tsman, Gregory N.
	Title	Development of a 30 THz heterodyne receiver based on a hot-electron-bolometer mixer			Type	Abstract
	Year	2014	Publication	Proc. 25^th Int. Symp. Space Terahertz Technol.	Abbreviated Journal	Proc. 25^th Int. Symp. Space Terahertz Technol.
	Volume		Issue		Pages	122
	Keywords	mid-IR NbN HEB mixers, GaAs substrates
	Abstract	We present new Hot-Electron-Bolometer (HEB) mixers designed for mid-IR spectroscopy targeting astrophysical and geophysical observations where high sensitivity and spectral resolution are required. The mixers are made of an ultrathin NbN film deposited on GaAs substrates. Two entirely different types of the devices have been fabricated. The first type is based on a direct radiation coupling concept and the mixing devices are shaped as squares of 5×5 μm 2 (which corresponds to the diffraction limit at the chosen wavelength) and 10×10 μm 2 (which was used to establish a possible influence of the contact pads on the radiation absorption). The second type utilizes a spiral antenna designed with HFSS. The fabrication and layout of the devices as well as the performance comparison will be presented. During the experiments, the HEB mixer was installed on the cold plate of a LHe cryostat. A germanium window and an extended semi-spherical germanium lens are used to couple the radiation. The cryostat is equipped with a germanium optical filter of thickness 0.5 mm and with a center wavelength of 10.6 mμ. The incident power absorption is measured by using the isothermal method. As a Local Oscillator, a 10.6 micrometers line of a CO2 gas laser is used. We further characterize the frequency response of the spiral antenna with a FIR-spectrometer. The noise characteristics of the mixers are determined from a room temperature cold load and a heated black body at ~600 K as a hot load.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1364
Permanent link to this record



	Author	Shurakov, Alexander; Tong, Cheuk-yu E.; Blundell, Raymond; Gol’tsman, Gregory
	Title	A microwave pumped HEB direct detector using a homodyne readout scheme			Type	Abstract
	Year	2014	Publication	Proc. 25^th Int. Symp. Space Terahertz Technol.	Abbreviated Journal	Proc. 25^th Int. Symp. Space Terahertz Technol.
	Volume		Issue		Pages	129
	Keywords	waveguide NbN HEB detector, NEP
	Abstract	We report the results of our study on the noise performance of a fast THz detector based on the repurpose of hot electron bolometer mixer (HEB). Instead of operating with an elevated bath temperature, microwave power is injected into the HEB device, which enhances the sensitivity of the detector and at the same time provide a mechanism for reading out impedance changes of the device induced by the modulated incident THz radiation [1]. We have demonstrated an improvement of the detector’s optical noise equivalent power (NEP). Furthermore, by introducing a homodyne readout scheme based on a room temperature microwave mixer, the dynamic range of the detector is increased. The HEB devices used in this work were made of 4 nm thick NbN film. The detector chips were installed into a waveguide mixer block fitted with a corrugated horn, mounted on the cold plate of a liquid helium cryostat. The HEBs were operated at a bath temperature of 4.2 K. The signal beam was terminated on black bodies at ambient and liquid nitrogen temperatures. A chopper wheel placed in front of the cryostat window operating at a frequency of 1.48 kHz modulated the input load temperature of the detector. A cold mesh filter, centered at 830 GHz, was used to define the input signal power bandwidth. Microwave was injected through a broadband directional coupler inside the cryostat. Our experiments were mostly conducted at a pump frequency of 1.5 GHz. The reflected microwave power from the HEB device was fed into a cryogenic low noise amplifier (LNA). The output of the LNA was connected to the RF input port of a room temperature microwave mixer, which beat the reflected signal from the HEB using a copy of the original 1.5 GHz injection signal in a homodyne demodulation scheme. The amplitude of the detected power was measured by a lock-in amplifier, which was synchronized to the chopper frequency. Preliminary results yield an optical NEP of ~1 pW/ Hz 1/2 which corresponds to an improvement of a factor of 3 compared to [1], driven mainly by a lowering of the system noise floor. The dynamic range was also increased by similar amount. References 1. A. Shurakov et al. “A Microwave Pumped Hot Electron Bolometric Direct Detector,” submitted on Oct 18, 2013 to Appl. Phys. Let.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1365
Permanent link to this record



	Author	Tong, C. Edward; Trifonov, Andrey; Blundell, Raymond; Shurakov, Alexander; Gol’tsman, Gregory
	Title	A digital terahertz power meter based on an NbN thin film			Type	Abstract
	Year	2014	Publication	Proc. 25^th Int. Symp. Space Terahertz Technol.	Abbreviated Journal	Proc. 25^th Int. Symp. Space Terahertz Technol.
	Volume		Issue		Pages	170
	Keywords	waveguide NbN HEB mixers
	Abstract	We have further studied the effect of subjecting a superconducting Hot Electron Bolometer (HEB) element made from an NbN thin film to microwave radiation. Since the photon energy is weak, the microwave radiation does not simply heat the film, but generates a bi-static state, switching between the superconducting and normal states, upon the application of a small voltage bias. Indeed, a relaxation oscillation of a few MHz has previously been reported in this regime [1]. Switching between the superconducting and normal states modulates the reflected microwave pump power from the device. A simple homodyne setup readily recovers the spontaneous switching waveform in the time domain. The switching frequency is a function of both the bias voltage (DC heating) and the applied microwave power. In this work, we use a 0.8 THz HEB waveguide mixer for the purpose of demonstration. The applied microwave pump, coupled through a directional coupler, is at 1 GHz. Since the pump power is of the order of a few μW, a room temperature amplifier is sufficient to amplify the reflected pump power from the HEB mixer, which beats with the microwave source in a homodyne set-up. After further amplification, the switching waveform is passed onto a frequency counter. The typical frequency of the switching pulses is 3-5 MHz. It is found that the digital frequency count increases with higher microwave pump power. When the HEB mixer is subjected to additional optical power at 0.8 THz, the frequency count also increases. When we vary the incident optical power by using a wire grid attenuator, a linear relationship is observed between the frequency count and the applied optical power, over at least an order of magnitude of power. This phenomenon can be exploited to develop a digital power meter, using a very simple electronics setup. Further experiments are under way to determine the range of linearity and the accuracy of calibration transfer from the microwave to the THz regime. References 1. Y. Zhuang, and S. Yngvesson, “Detection and interpretation of bistatic effects in NbN HEB devices,” Proc. 13 th Int. Symp. Space THz Tech., 2002, pp. 463–472.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1366
Permanent link to this record



	Author	Lusche, R.; Semenov, A.; Korneeva, Y.; Trifonov, A.; Korneev, A.; Gol'tsman, G.; Hübers, H.-W.
	Title	Effect of magnetic field on the photon detection in thin superconducting meander structures			Type	Journal Article
	Year	2014	Publication	Phys. Rev. B	Abbreviated Journal	Phys. Rev. B
	Volume	89	Issue	10	Pages	104513 (1 to 7)
	Keywords	NbN SSPD, SNSPD
	Abstract	We have studied the influence of an externally applied magnetic field on the photon and dark count rates of meander-type niobium nitride superconducting nanowire single-photon detectors. Measurements have been performed at a temperature of 4.2 K, and magnetic fields up to 250 mT have been applied perpendicularly to the meander plane. While photon count rates are field independent at weak applied fields, they show a strong dependence at fields starting from approximately ±25 mT. This behavior, as well as the magnetic field dependence of the dark count rates, is in good agreement with the recent theoretical model of vortex-assisted photon detection and spontaneous vortex crossing in narrow superconducting lines. However, the local reduction of the superconducting free energy due to photon absorption, which is the fitting parameter in the model, increases much slower with the photon energy than the model predicts. Furthermore, changes in the free-energy during photon counts and dark counts depend differently on the current that flows through the meander. This indicates that photon counts and dark counts occur in different parts of the meander.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1098-0121	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1367
Permanent link to this record



	Author	Ozhegov, R. V.; Gorshkov, K. N.; Vachtomin, Y. B.; Smirnov, K. V.; Finkel, M. I.; Goltsman, G. N.; Kiselev, O. S.; Kinev, N. V.; Filippenko, L. V.; Koshelets, V. P.
	Title	Terahertz imaging system based on superconducting heterodyne integrated receiver			Type	Conference Article
	Year	2014	Publication	Proc. THz and Security Applications	Abbreviated Journal	Proc. THz and Security Applications
	Volume		Issue		Pages	113-125
	Keywords	SIS mixer, SIR, THz imaging
	Abstract	The development of terahertz imaging instruments for security systems is on the cutting edge of terahertz technology. We are developing a THz imaging system based on a superconducting integrated receiver (SIR). An SIR is a new type of heterodyne receiver based on an SIS mixer integrated with a flux-flow oscillator (FFO) and a harmonic mixer which is used for phase-locking the FFO. Employing an SIR in an imaging system means building an entirely new instrument with many advantages compared to traditional systems. In this project we propose a prototype THz imaging system using an 1 pixel SIR and 2D scanner. At a local oscillator frequency of 500 GHz the best noise equivalent temperature difference (NETD) of the SIR is 10 mK at an integration time of 1 s and a detection bandwidth of 4 GHz. The scanner consists of two rotating flat mirrors placed in front of the antenna consisting of a spherical primary reflector and an aspherical secondary reflector. The diameter of the primary reflector is 0.3 m. The operating frequency of the imaging system is 600 GHz, the frame rate is 0.1 FPS, the scanning area is 0.5 × 0.5 m2, the image resolution is 50 × 50 pixels, the distance from an object to the scanner was 3 m. We have obtained THz images with a spatial resolution of 8 mm and a NETD of less than 2 K.
	Address
	Corporate Author				Thesis
	Publisher	Springer Netherlands	Place of Publication	Dordrecht	Editor	Corsi, C.; Sizov, F.
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	978-94-017-8828-1	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1368
Permanent link to this record



	Author	Peltonen, J. T.; Astafiev, O. V.; Korneeva, Y. P.; Voronov, B. M.; Korneev, A. A.; Charaev, I. M.; Semenov, A. V.; Golt'sman, G. N.; Ioffe, L. B.; Klapwijk, T. M.; Tsai, J. S.
	Title	Coherent flux tunneling through NbN nanowires			Type	Journal Article
	Year	2013	Publication	Phys. Rev. B	Abbreviated Journal	Phys. Rev. B
	Volume	88	Issue	22	Pages	220506 (1 to 5)
	Keywords	NbN nanowires
	Abstract	We demonstrate evidence of coherent magnetic flux tunneling through superconducting nanowires patterned in a thin highly disordered NbN film. The phenomenon is revealed as a superposition of flux states in a fully metallic superconducting loop with the nanowire acting as an effective tunnel barrier for the magnetic flux, and reproducibly observed in different wires. The flux superposition achieved in the fully metallic NbN rings proves the universality of the phenomenon previously reported for InOx. We perform microwave spectroscopy and study the tunneling amplitude as a function of the wire width, compare the experimental results with theories, and estimate the parameters for existing theoretical models.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1098-0121	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1369
Permanent link to this record



	Author	Beck, M.; Rousseau, I.; Klammer, M.; Leiderer, P.; Mittendorff, M.; Winnerl, S.; Helm, M.; Gol'tsman, G.N.; Demsar, J.
	Title	Transient increase of the energy gap of superconducting NbN thin films excited by resonant narrow-band terahertz pulses			Type	Journal Article
	Year	2013	Publication	Phys. Rev. Lett.	Abbreviated Journal	Phys. Rev. Lett.
	Volume	110	Issue	26	Pages	267003 (1 to 5)
	Keywords	NbN thin films, energy gap
	Abstract	Observations of radiation-enhanced superconductivity have thus far been limited to a few type-I superconductors (Al, Sn) excited at frequencies between the inelastic scattering rate and the superconducting gap frequency 2Delta/h. Utilizing intense, narrow-band, picosecond, terahertz pulses, tuned to just below and above 2Delta/h of a BCS superconductor NbN, we demonstrate that the superconducting gap can be transiently increased also in a type-II dirty-limit superconductor. The effect is particularly pronounced at higher temperatures and is attributed to radiation induced nonthermal electron distribution persisting on a 100 ps time scale.
	Address	Department of Physics and Center for Applied Photonics, University of Konstanz, D-78457, Germany
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0031-9007	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:23848912			Approved	no
	Call Number				Serial	1370
Permanent link to this record



	Author	Zhang, W.; Miao, W.; Li, S. L.; Zhou, K. M.; Shi, S. C.; Gao, J. R.; Goltsman, G. N.
	Title	Measurement of the spectral response of spiral-antenna coupled superconducting hot electron bolometers			Type	Journal Article
	Year	2013	Publication	IEEE Trans. Appl. Supercond.	Abbreviated Journal	IEEE Trans. Appl. Supercond.
	Volume	23	Issue	3	Pages	2300804-2300804
	Keywords	NbN HEB detector
	Abstract	Measured spectral response of spiral-antenna coupled superconducting hot electron bolometers (HEBs) often drops dramatically at frequencies that are still within the frequency range of interest (e.g., ~ 5 THz). This is inconsistent with the implied low receiver noise temperatures from the same measurements. To understand this discrepancy, we exhaustively test and calibrate the thermal sources used in Fourier transform spectrometer measurements. We first investigate the absolute emission spectrum of high-pressure Hg arc lamp, then measure the spectral response of two spiral-antenna coupled NbN HEBs with a Martin-Puplett interferometer as spectrometer and 77 K blackbody as broadband signal source. The measured absolute emission spectrum of Hg arc lamp is proportional to frequency, corresponding to an equivalent blackbody temperature of 4000 K at 1 THz, 1500 K at 3 THz, and 800 K at 5 THz, respectively. Measured spectral response of spiral-antenna coupled NbN HEBs, corrected for air absorption, is nearly flat in the frequency range of 0.5-4 THz, consistent with simulated coupling efficiency between HEB and spiral-antenna. These results explain the discrepancy, and prove that spiral-antenna coupled superconducting NbN HEBs work well in a wide frequency range. In addition, this calibration method and these results are broadly applicable to other quasi-optical THz receivers.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1051-8223	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1371
Permanent link to this record



	Author	Shurakov, A.; Tong, C.-Y. E.; Blundell, R.; Kaurova, N.; Voronov, B.; Gol'tsman, G.
	Title	Microwave stabilization of a HEB mixer in a pulse-tube cryocooler			Type	Journal Article
	Year	2013	Publication	IEEE Trans. Appl. Supercond.	Abbreviated Journal	IEEE Trans. Appl. Supercond.
	Volume	23	Issue	3	Pages	1501504-1501504
	Keywords	NbN HEB mixers
	Abstract	We report the results of our study of the stability of an 800 GHz hot electron bolometer (HEB) mixer cooled with a pulse-tube cryocooler. Pulse-tube cryocoolers introduce temperature fluctuations as well as mechanical vibrations at a frequency of ~1 Hz, both of which can cause receiver gain fluctuations at that frequency. In our system, the motor of the cryocooler was separated from the cryostat to minimize mechanical vibrations, leaving thermal effects as the dominant source of the receiver gain fluctuations. We measured root mean square temperature variations of the 4 K stage of ~7 mK. The HEB mixer was pumped by a solid state local oscillator at 810 GHz. The root mean square current fluctuations at the low noise operating point (1.50 mV, 56.5 μA) were ~0.12 μA, and were predominantly due to thermal fluctuations. To stabilize the bias current, microwave radiation was injected to the HEB mixer. The injected power level was set by a proportional-integral-derivative controller, which completely compensates for the bias current oscillations induced by the pulse-tube cryocooler. Significant improvement in the Allan variance of the receiver output power was obtained, and an Allan time of 5 s was measured.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1051-8223	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1372
Permanent link to this record



	Author	Schuck, C.; Pernice, W. H. P.; Minaeva, O.; Li, Mo; Gol'tsman, G.; Sergienko, A. V.; Tang, H. X.
	Title	Matrix of integrated superconducting single-photon detectors with high timing resolution			Type	Journal Article
	Year	2013	Publication	IEEE Trans. Appl. Supercond.	Abbreviated Journal	IEEE Trans. Appl. Supercond.
	Volume	23	Issue	3	Pages	2201007-2201007
	Keywords	NbN SSPD, SNSPD, array, matrix
	Abstract	We demonstrate a large grid of individually addressable superconducting single photon detectors on a single chip. Each detector element is fully integrated into an independent waveguide circuit with custom functionality at telecom wavelengths. High device density is achieved by fabricating the nanowire detectors in traveling wave geometry directly on top of silicon-on-insulator waveguides. Our superconducting single photon detector matrix includes detector designs optimized for high detection efficiency, low dark count rate, and high timing accuracy. As an example, we exploit the high timing resolution of a particularly short nanowire design to resolve individual photon round-trips in a cavity ring-down measurement of a silicon ring resonator.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1051-8223	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1373
Permanent link to this record



	Author	Lusche, Robert; Semenov, Alexey; Huebers, Heinz-Willhelm; Ilin, Konstantin; Siegel, Michael; Korneeva, Yuliya; Trifonov, Andrey; Korneev, Alexander; Goltsman, Gregory
	Title	Effect of the wire geometry and an externally applied magnetic field on the detection efficiency of superconducting nanowire single-photon detectors			Type	Abstract
	Year	2013	Publication	INIS	Abbreviated Journal	INIS
	Volume	46	Issue	8	Pages	1-3
	Keywords	TaN, NbN SSPD, SNSPD
	Abstract	The interest in single-photon detectors in the near-infrared wavelength regime for applications, e.g. in quantum cryptography has immensely increased in the last years. Superconducting nanowire single-photon detectors (SNSPD) already show quite reasonable detection efficiencies in the NIR which can even be further improved. Novel theoretical approaches including vortex-assisted photon counting state that the detection efficiency in the long wavelength region can be enhanced by the detector geometry and an applied magnetic field. We present spectral measurements in the wavelength range from 350-2500 nm of the detection efficiency of meander-type TaN and NbN SNSPD with varying nanowire line width from 80 to 250 nm. Due to the used experimental setup we can accurately normalize the measured spectra and are able to extract the intrinsic detection efficiency (IDE) of our detectors. The results clearly indicate an improvement of the IDE depending on the wire width according to the theoretic models. Furthermore we experimentally found that the smallest detectable photon-flux can be increased by applying a small magnetic field to the detectors.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1374
Permanent link to this record



	Author	Pernice, W. H. P.; Schuck, C.; Minaeva, O.; Li, M.; Goltsman, G. N.; Sergienko, A. V.; Tang, H. X.
	Title	High-speed and high-efficiency travelling wave single-photon detectors embedded in nanophotonic circuits			Type	Journal Article
	Year	2012	Publication	Nat. Commun.	Abbreviated Journal	Nat. Commun.
	Volume	3	Issue		Pages	1325 (1 to 10)
	Keywords	waveguide SSPD
	Abstract	Ultrafast, high-efficiency single-photon detectors are among the most sought-after elements in modern quantum optics and quantum communication. However, imperfect modal matching and finite photon absorption rates have usually limited their maximum attainable detection efficiency. Here we demonstrate superconducting nanowire detectors atop nanophotonic waveguides, which enable a drastic increase of the absorption length for incoming photons. This allows us to achieve high on-chip single-photon detection efficiency up to 91% at telecom wavelengths, repeatable across several fabricated chips. We also observe remarkably low dark count rates without significant compromise of the on-chip detection efficiency. The detectors are fully embedded in scalable silicon photonic circuits and provide ultrashort timing jitter of 18 ps. Exploiting this high temporal resolution, we demonstrate ballistic photon transport in silicon ring resonators. Our direct implementation of a high-performance single-photon detector on chip overcomes a major barrier in integrated quantum photonics.
	Address	Department of Electrical Engineering, Yale University, New Haven, Connecticut 06511, USA
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2041-1723	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:23271658; PMCID:PMC3535416			Approved	no
	Call Number				Serial	1375
Permanent link to this record



	Author	Lusche, R.; Semenov, A.; Il'in, K.; Korneeva, Y.; Trifonov, A.; Korneev, A.; Hubers, H.; Siegel, M.; Gol'tsman, G.
	Title	Effect of the wire width and magnetic field on the intrinsic detection efficiency of superconducting nanowire single-photon detectors			Type	Journal Article
	Year	2013	Publication	IEEE Trans. Appl. Supercond.	Abbreviated Journal	IEEE Trans. Appl. Supercond.
	Volume	23	Issue	3	Pages	2200205-2200205
	Keywords	SSPD, SNSPD
	Abstract	We present thorough measurements of the intrinsic detection efficiency in the wavelength range from 350 to 2500 nm for meander-type TaN and NbN superconducting nanowire single-photon detectors with different widths of the nanowire. The width varied from 70 nm to 130 nm. The open-beam configuration allowed us to accurately normalize measured spectra and to extract the intrinsic detection efficiency. For detectors from both materials the intrinsic detection efficiency at short wavelengths amounts at 100% and gradually decreases at wavelengths larger than the specific cut-off wavelengths, which decreases with the width of the nanowire. Furthermore, we show that applying weak magnetic fields perpendicular to the meander plane decreases the smallest detectable photon flux.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1051-8223	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1376
Permanent link to this record



	Author	Tuchak, A. N.; Gol’tsman, G. N.; Kitaeva, G. K.; Penin, A. N.; Seliverstov, S. V.; Finkel, M. I.; Shepelev, A. V.; Yakunin, P. V.
	Title	Generation of nanosecond terahertz pulses by the optical rectification method			Type	Journal Article
	Year	2012	Publication	JETP Lett.	Abbreviated Journal	JETP Lett.
	Volume	96	Issue	2	Pages	94-97
	Keywords	optical rectification, lithium niobate crystal
	Abstract	The possibility of the generation of quasi-cw terahertz radiation by the optical rectification method for broad-band Fourier unlimited nanosecond laser pulses has been experimentally demonstrated. The broadband radiation of a LiF dye-center laser is used as a pump source of a nonlinear optical oscillator. The energy efficiency of terahertz optical frequency conversion in a periodically polarized lithium niobate crystal is 4 × 10−9 at a pump power density of 7 MW/cm2.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0021-3640	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1377
Permanent link to this record



	Author	Pentin, I. V.; Smirnov, A. V.; Ryabchun, S. A.; Ozhegov, R. V.; Gol’tsman, G. N.; Vaks, V. L.; Pripolzin, S. I.; Pavel’ev, D. G.; Koshurinov, Y. I.; Ivanov, A. S.
	Title	Semiconducting superlattice as a solid-state terahertz local oscillator for NbN hot-electron bolometer mixers			Type	Journal Article
	Year	2012	Publication	Tech. Phys.	Abbreviated Journal	Tech. Phys.
	Volume	57	Issue	7	Pages	971-974
	Keywords	semiconducting superlattice frequency multiplier, NbN HEB mixers
	Abstract	We present the results of our studies of the semiconducting superlattice (SSL) frequency multiplier and its application as part of the solid state local oscillator (LO) in the terahertz heterodyne receiver based on a NbN hot-electron bolometer (HEB) mixer. We show that the SSL output power level increases as the ambient temperature is lowered to 4.2 K, the standard HEB operation temperature.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1063-7842	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1378
Permanent link to this record



	Author	Rasulova, G. K.; Brunkov, P. N.; Pentin, I. V.; Egorov, A. Y.; Knyazev, D. A.; Andrianov, A. V.; Zakhar’in, A. O.; Konnikov, S. G.; Gol’tsman, G. N.
	Title	A weakly coupled semiconductor superlattice as a potential for a radio frequency modulated terahertz light emitter			Type	Journal Article
	Year	2012	Publication	Appl. Phys. Lett.	Abbreviated Journal	Appl. Phys. Lett.
	Volume	100	Issue	13	Pages	131104 (1 to 4)
	Keywords	semiconductor superlattice
	Abstract	The bolometer response to THz radiation from a weakly coupled GaAs/AlGaAs superlattice biased in the self-oscillations regime has been observed. The bolometer signal is modulated with the frequency equal to the fundamental frequency of superlattice self-oscillations. The frequency spectrum of the bolometer signal contains higher harmonics whose frequency is a multiple of fundamental frequency of self-oscillations. This work was supported by State Contracts Nos. 16.740.11.0044 and 16.552.11.7002 of Ministry of Education and Science of the Russian Federation. Structural characterization was made on the equipment of the Joint Research Centre «Material science and characterization in advanced technology» (Ioffe Institute, St. Petersburg, Russia).
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0003-6951	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1379
Permanent link to this record



	Author	Sclafani, M.; Marksteiner, M.; Keir, F. M. L.; Divochiy, A.; Korneev, A.; Semenov, A.; Gol'tsman, G.; Arndt, M.
	Title	Sensitivity of a superconducting nanowire detector for single ions at low energy			Type	Journal Article
	Year	2012	Publication	Nanotechnol.	Abbreviated Journal	Nanotechnol.
	Volume	23	Issue	6	Pages	065501 (1 to 5)
	Keywords	NbN SSPD, SNSPD, superconducting single ion detector, SSID, SNSID
	Abstract	We report on the characterization of a superconducting nanowire detector for ions at low kinetic energies. We measure the absolute single-particle detection efficiency eta and trace its increase with energy up to eta = 100%. We discuss the influence of noble gas adsorbates on the cryogenic surface and analyze their relevance for the detection of slow massive particles. We apply a recent model for the hot-spot formation to the incidence of atomic ions at energies between 0.2 and 1 keV. We suggest how the differences observed for photons and atoms or molecules can be related to the surface condition of the detector and we propose that the restoration of proper surface conditions may open a new avenue for SSPD-based optical spectroscopy on molecules and nanoparticles.
	Address	Vienna Center for Quantum Science and Technology, Faculty of Physics, University of Vienna, Vienna, Austria
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language	English	Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0957-4484	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:22248823			Approved	no
	Call Number				Serial	1380
Permanent link to this record



	Author	Zhang, W.; Miao, W.; Yao, Q. J.; Lin, Z. H.; Shi, S. C.; Gao, J. R.; Goltsman, G. N.
	Title	Spectral response and noise temperature of a 2.5 THz spiral antenna coupled NbN HEB mixer			Type	Journal Article
	Year	2012	Publication	Phys. Procedia	Abbreviated Journal	Phys. Procedia
	Volume	36	Issue		Pages	334-337
	Keywords	NbN HEB mixer
	Abstract	We report on a 2.5 THz spiral antenna coupled NbN hot electron bolometer (HEB) mixers, fabricated with in-situ process. The receiver noise temperature with lowest value of 1180 K is in good agreement with calculated quantum efficiency factor as a function of bias voltage. In addition, the measured spectral response of the spiral antenna coupled NbN HEB mixer shows broad frequency coverage of 0.8-3 THz, and corrected response for optical losses, FTS, and coupling efficiency between antenna and bolometer falls with frequency due to diffraction-limited beam of lens/antenna combination.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1875-3892	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1381
Permanent link to this record



	Author	Korneev, A.; Korneeva, Y.; Florya, I.; Voronov, B.; Goltsman, G.
	Title	NbN nanowire superconducting single-photon detector for mid-infrared			Type	Journal Article
	Year	2012	Publication	Phys. Procedia	Abbreviated Journal	Phys. Procedia
	Volume	36	Issue		Pages	72-76
	Keywords	NbN SSPD, SNSPD
	Abstract	Superconducting single-photon detectors (SSPD) is typically 100 nm-wide supercondiucting strip in a shape of meander made of 4-nm-thick ﬁlm. To reduce response time and increase voltage response a parallel connection of the strips was proposed. Recently we demonstrated that reduction of the strip width improves the quantum effciency of such a detector at wavelengths longer than 1.5 μm. Being encourage by this progress in quantum effciency we improved the fabrication process and made parallel-wire SSPD with 40-nm-wide strips covering total area of 10 μm x 10 μm. In this paper we present the results of the characterization of such a parallel-wire SSPD at 10.6 μm wavelength and demonstrate linear dependence of the count rate on the light power as it should be in case of single-photon response.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1875-3892	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1382
Permanent link to this record



	Author	Beck, Matthias; Leiderer, Paul; Kabanov, Viktor V.; Gol'tsman, Gregory; Helm, Manfred; Demsar, Jure
	Title	Energy-gap dynamics of a superconductor NbN studied by time-resolved terahertz spectroscopy			Type	Abstract
	Year	2012	Publication	INIS	Abbreviated Journal	INIS
	Volume	45	Issue	12	Pages	1-3
	Keywords	NbN energy gap
	Abstract	Using time-resolved terahertz (THz) spectroscopy we performed direct studies of the photoinduced suppression and recovery of the SC gap in a conventional SC NbN. Both processes are found to be strongly temperature and excitation density dependent. The analysis of the data with the established phenomenological Rothwarf-Taylor model enabled us to determine the important microscopic constants: the Cooper pair-breaking rate via phonon absorption and the bare quasiparticle recombination rate. From the latter we were able to extract the dimensionless electron-phonon coupling constant, λ=1.1±0.1, in excellent agreement with theoretical estimates. The technique also allowed us to determine the absorbed energy required to suppress SC, which in NbN equals the thermodynamic condensation energy (in cuprates the two differ by an order of magnitude). Finally, we present the first studies of dynamics following resonant excitation with intense narrow band THz pulses tuned to above and below the superconducting gap. These suggest an additional process, particularly pronounced near Tc, that could be attributed to amplification of SC via effective quasiparticle cooling.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1383
Permanent link to this record



	Author	Pentin, I. V.; Smirnov, A. V.; Ryabchun, S. A.; Gol’tsman, G. N.; Vaks, V. L.; Pripolzin, S. I.; Paveliev, D. G.
	Title	Heterodyne source of THz range based on semiconductor superlattice multiplier			Type	Conference Article
	Year	2011	Publication	IRMMW-THz	Abbreviated Journal	IRMMW-THz
	Volume		Issue		Pages	1-2
	Keywords	NbN HEB mixer, superlattice
	Abstract	We present the results of our studies of the possibility of developing a heterodyne receiver incorporating a hot-electron bolometer mixer as the detector and a semiconductor superlattice multiplier driven by a reference synthesizer as the local oscillator. We observe that such a local oscillator offers enough power in the terahertz range to pump the HEB into the operating state.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number	6105209			Serial	1384
Permanent link to this record



	Author	Ryabchun, S.; Smirnov, A.; Pentin, I.; Vakhtomin, Yu.; Smirnov, K.; Kaurova, N.; Voronov, B.; Goltsman, G.
	Title	Superconducting single photon detector integrated with optical cavity			Type	Conference Article
	Year	2011	Publication	Proc. MLPLIT	Abbreviated Journal	Proc. MLPLIT
	Volume		Issue		Pages	143-145
	Keywords	NbN SSPD, cavity
	Abstract
	Address	Suzdal / Vladimir (Russia)
	Corporate Author				Thesis
	Publisher	Modern laser physics and laser-information technologies for science and manufacture	Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference	1st international russian-chinese conference / youthschool-workshop
	Notes	September 23-28, 2011			Approved	no
	Call Number				Serial	1385
Permanent link to this record



	Author	Maslennikova, A.; Larionov, P.; Ryabchun, S.; Smirnov, A.; Pentin, I.; Vakhtomin, Yu.; Smirnov, K.; Kaurova, N.; Voronov, B.; Goltsman, G.
	Title	Noise equivalent power and dynamic range of NBN hot-electron bolometers			Type	Conference Article
	Year	2011	Publication	Proc. MLPLIT	Abbreviated Journal	Proc. MLPLIT
	Volume		Issue		Pages	146-148
	Keywords	NbN HEB
	Abstract
	Address	Suzdal / Vladimir (Russia)
	Corporate Author				Thesis
	Publisher	Modern laser physics and laser-information technologies for science and manufacture	Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference	1st international russian-chinese conference / youthschool-workshop
	Notes	September 23-28, 2011			Approved	no
	Call Number				Serial	1386
Permanent link to this record



	Author	Korneev, A.; Korneeva, Y.; Florya, I.; Voronov, B.; Goltsman, G.
	Title	Spectral sensitivity of narrow strip NbN superconducting single-photon detector			Type	Conference Article
	Year	2011	Publication	Proc. SPIE	Abbreviated Journal	Proc. SPIE
	Volume	8072	Issue		Pages	80720G (1 to 9)
	Keywords	NbN SSPD, SNSPD
	Abstract	Superconducting single-photon detector (SSPD) is patterned from 4-nm-thick NbN film deposited on sapphire substrate as a 100-nm-wide strip. Due to its high detection efficiency, low dark counts, and picosecond timing jitter SSPD has become a competitor to the InGaAs avalanche photodiodes at 1550 nm and longer wavelengths. Although the SSPD is operated at liquid helium temperature its efficient single-mode fibre coupling enabled its usage in many applications ranging from single-photon sources research to quantum cryptography. In our strive to increase the detection efficiency at 1550 nm and longer wavelengths we developed and fabricated SSPD with the strip almost twice narrower compared to the standard 100 nm. To increase the voltage response of the device we utilized cascade switching mechanism: we connected 50-nm-wide and 10-Î¼m-long strips in parallel covering the area of 10 Î¼mx10 μm. Absorption of a photon breaks the superconductivity in a strip leading to the bias current redistribution between other strips followed their cascade switching. As the total current of all the strips about is 1 mA by the order of magnitude the response voltage of such an SSPD is several times higher compared to the traditional meander-shaped SSPDs. In middle infrared (about 3 Î¼m wavelength) these devices have the detection efficiency several times higher compared to the traditional SSPDs.
	Address
	Corporate Author				Thesis
	Publisher	SPIE	Place of Publication		Editor	Fiurásek, J.; Prochazka, I.
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference	Photon Counting Applications, Quantum Optics, and Quantum Information Transfer and Processing III
	Notes				Approved	no
	Call Number				Serial	1387
Permanent link to this record



	Author	Beck, M.; Klammer, M.; Lang, S.; Leiderer, P.; Kabanov, V. V.; Gol’tsman, G. N.; Demsar, J.
	Title	Energy-gap dynamics of superconducting NbN thin films studied by time-resolved terahertz spectroscopy			Type	Miscellaneous
	Year	2011	Publication	arXiv	Abbreviated Journal
	Volume		Issue		Pages
	Keywords	NbN thin film, energy gap dynamics
	Abstract	Using time-domain Terahertz spectroscopy we performed direct studies of the photoinduced suppression and recovery of the superconducting gap in a conventional BCS superconductor NbN. Both processes are found to be strongly temperature and excitation density dependent. The analysis of the data with the established phenomenological Rothwarf-Taylor model enabled us to determine the bare quasiparticle recombination rate, the Cooper pair-breaking rate and the electron-phonon coupling constant, \lambda = 1.1 +/- 0.1, which is in excellent agreement with theoretical estimates.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes	Duplicated as 641			Approved	no
	Call Number				Serial	1388
Permanent link to this record



	Author	Tret’yakov, I. V.; Ryabchun, S. A.; Kaurova, N. S.; Larionov, P. A.; Lobastova, A. A.; Voronov, B. M.; Finkel, M. I.; Gol’tsman, G. N.
	Title	Optimum absorbed heterodyne power for superconducting NbN hot-electron bolometer mixer			Type	Journal Article
	Year	2010	Publication	Tech. Phys. Lett.	Abbreviated Journal	Tech. Phys. Lett.
	Volume	36	Issue	12	Pages	1103-1105
	Keywords	NbN HEB mixer
	Abstract	Absorbed heterodyne power has been measured in a low-noise broadband hot-electron bolometer (HEB) mixer for the terahertz range, operating on the effect of electron heating in the resistive state of an ultrathin superconducting NbN film. It is established that the optimum absorbed heterodyne power for the HEB mixer operating at 2.5 THz is about 100 nW.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1063-7850	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1389
Permanent link to this record



	Author	Ozhegov, R. V.; Gorshkov, K. N.; Okunev, O. V.; Gol’tsman, G. N.
	Title	Superconducting hot-electron bolometer mixer as element of thermal imager matrix			Type	Journal Article
	Year	2010	Publication	Tech. Phys. Lett.	Abbreviated Journal	Tech. Phys. Lett.
	Volume	36	Issue	11	Pages	1006-1008
	Keywords	HEB mixers
	Abstract	The possibility of using a matrix of sensitive elements on a 12-mm-diameter hyperhemispherical lens in a thermal imager operating in the terahertz range has been studied. Dimensions of a lens region acceptable for arrangement of the matrix, in which the receiver noise temperature varies within 16% of the mean value, are determined to be 3.3% of the lens diameter. Deviations of the main lobe of the directivity pattern are evaluated, which amount to ±1.25° relative to the direction toward the optimum position of a mixer. The fluctuation sensitivity of the receiver measured in experiment is 0.5 K at a frequency of 300 GHz.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1063-7850	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1390
Permanent link to this record



	Author	Palma, F.; Teppe, F.; Fatimy, A. E.; Green, R.; Xu, J.; Vachontin, Y.; Tredicucci, A.; Goltsman, G.; Knap, W.
	Title	THz communication system based on a THz quantum cascade laser and a hot electron bolometer			Type	Conference Article
	Year	2010	Publication	35th Int. Conf. Infrared, Millimeter, and Terahertz Waves	Abbreviated Journal	35th Int. Conf. Infrared, Millimeter, and Terahertz Waves
	Volume		Issue		Pages	11623798 (1 to 2)
	Keywords	QCL, HEB detector
	Abstract	We present the experimental study of the direct emission – detection system based on the THz Quantum Cascade Laser as a source and Hot Electron Bolometer (HEB) detector – in view of its application as an optical communication system. We show that the system can efficiently transmit the QCL Terahertz pulses. We estimate the maximal modulation speed of the system to be about several GHz and show that it is limited only by the QCL pulse power supply, detector amplifier and connection line/wires parameters.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1391
Permanent link to this record



	Author	Maingault, L.; Tarkhov, M.; Florya, I.; Semenov, A.; Espiau de Lamaëstre, R.; Cavalier, P.; Gol’tsman, G.; Poizat, J.-P.; Villégier, J.-C.
	Title	Spectral dependency of superconducting single photon detectors			Type	Journal Article
	Year	2010	Publication	J. Appl. Phys.	Abbreviated Journal	J. Appl. Phys.
	Volume	107	Issue	11	Pages	116103 (1 to 3)
	Keywords	NbN SSPD, SNSPD
	Abstract	We investigate the effect of varying both incoming optical wavelength and width of NbN nanowires on the superconducting single photon detectors (SSPD) detection efficiency. The SSPD are current biased close to critical value and temperature fixed at 4.2 K, far from transition. The experimental results are found to verify with a good accuracy predictions based on the “hot spot model,” whose size scales with the absorbed photon energy. With larger optical power inducing multiphoton detection regime, the same scaling law remains valid, up to the three-photon regime. We demonstrate the validity of applying a limited number of measurements and using such a simple model to reasonably predict any SSPD behavior among a collection of nanowire device widths at different photon wavelengths. These results set the basis for designing efficient single photon detectors operating in the infrared (2–5 μm range). This work was supported by European projects FP6 STREP “SINPHONIA” (Contract No. NMP4-CT-2005-16433) and IP “QAP” (Contract No. 15848).
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0021-8979	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1392
Permanent link to this record



	Author	Maslennikova, Anna; Tretyakov, Ivan; Ryabchun, Sergey; Finkel, Matvey; Kaurova, Natalia; Voronov, Boris; Gol’tsman, Gregory
	Title	Gain bandwidth and noise temperature of NbN HEB mixers with simultaneous phonon and diffusion cooling			Type	Abstract
	Year	2010	Publication	Proc. 21^th Int. Symp. Space Terahertz Technol.	Abbreviated Journal	Proc. 21^th Int. Symp. Space Terahertz Technol.
	Volume		Issue		Pages	218-219
	Keywords
	Abstract	The space observatory Millimetron will be operating in the millimeter, sub-millimeter and infrared ranges using a 12-m cryogenic telescope in a single-dish mode, and as an interferometer with the space-earth and space-space baselines (the latter after the launch of the second identical space telescope). The observatory will allow performing astronomical observations with an unprecedented sensitivity (down to nJy level) in the single-dish mode, and observations with a high angular resolution in the interferometer mode. The total spectral range 20 μm – 2 cm is separated into 10 bands. HEB mixers with two cooling channels (diffusion and phonon) have been chosen to be the detectors of choice of the system covering the range from 1 THz to 6 THz as the best detectors in terahertz receivers. This type of HEB has already shown good work in the terahertz range. A gain bandwidth of 6 GHz at an LO frequency of 300 GHz and a noise temperature of 750 K at an LO frequency of 2.5 THz are the best values for HEB mixers with two cooling channels [1]. Theoretical estimations predict a bandwidth up to 12 GHz. Reaching such good result demands more systematic and thorough research. We present the results of the gain bandwidth and noise temperature measurements for superconducting hot- electron bolometer mixers with two cooling channels. These characteristics of the devices of lengths varying from 50 to 200 nm were measured for the purposes of Millimetron at frequencies of 600 GHz, 2.5 THz, and 3.8 THz. For gain bandwidth measurements we use two BWO’s operating at 600 GHz: one as the signal and the second as the LO. The noise temperature measurements were performed using a gas discharge laser as the LO and blackbodies at 77 K and 295 K as input signals. The devices studied consist of 3.5-nm-thick NbN bridges connected to thick (10 nm) high conductivity Au leads fabricated in situ. This method of fabricating devices has already proved promising by opening the diffusion cooling channel. [2] Fig. 1 shows a SEM photograph of a log-spiral antenna with an HEB at its apex. Fig. 1. Left: a SEM photograph of a log-spiral antenna with an HEB at its apex; right: a close-up of the HEB at the antenna apex. [1] S. A. Ryabchun, I. V. Tretyakov, M. I. Finkel, S. N. Maslennikov, N. S. Kaurova, V. A. Seleznev, B. M. Voronov, and G. N. Gol’tsman, NbN phonon-cooled hot-electron bolometer mixer with additional diffusion cooling, Proc. of the 20 th Int. Symp. Space. Technol., Charlottesville, Virginia, USA, April 20 – 22, 2009. 218[2] S. A. Ryabchun * , I. V. Tretyakov, M. I. Finkel, S. N. Maslennikov, N. S. Kaurova, V. A. Seleznev, B. M. Voronov and G. N. Goltsman, Fabrication and characterisation of NbN HEB mixers with in situ gold contacts, Proc. of the 19 th Int. Symp. Space. Technol., Groningen, The Netherlands, April 28-30, 2008
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1393
Permanent link to this record



	Author	Lobanov, Yury V.; Tong, Cheuk-yu E.; Hedden, Abigail S.; Blundell, Raymond; Gol’tsman, Gregory N.
	Title	Microwave-assisted measurement of the frequency response of terahertz HEB mixers with a Fourier transform spectrometer			Type	Conference Article
	Year	2010	Publication	Proc. 21^th Int. Symp. Space Terahertz Technol.	Abbreviated Journal	Proc. 21^th Int. Symp. Space Terahertz Technol.
	Volume		Issue		Pages	420-423
	Keywords
	Abstract	We describe a novel method of operation of the HEB direct detector for use with a Fourier Transform Spectrometer. Instead of elevating the bath temperature, we have measured the RF response of waveguide HEB mixers by applying microwave radiation to select appropriate bias conditions. In our experiment, a microwave signal is injected into the HEB mixer via its IF port. By choosing an appropriate injection level, the device can be operated close to the desired operating point. Furthermore, we have shown that both thermal biasing and microwave injection can reproduce the same spectral response of the HEB mixer. However, with the use of microwave injection, there is no need to wait for the mixer to reach thermal equilibrium, so characterisation can be done in less time. Also, the liquid helium consumption for our wet cryostat is also reduced. We have demonstrated that the signal- to-noise ratio of the FTS measurements can be improved with microwave injection.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1394
Permanent link to this record



	Author	Zinoni, C.; Alloing, B.; Li, L. H.; Marsili, F.; Fiore, A.; Lunghi, L.; Gerardino, A.; Vakhtomin, Y. B.; Smirnov, K. V.; Gol’tsman, G. N.
	Title	Erratum: “Single photon experiments at telecom wavelengths using nanowire superconducting detectors” [Appl. Phys. Lett. 91, 031106 (2007)]			Type	Journal Article
	Year	2010	Publication	Appl. Phys. Lett.	Abbreviated Journal	Appl. Phys. Lett.
	Volume	96	Issue	8	Pages	089901
	Keywords	SSPD, SNSPD, erratum
	Abstract	A calculation error was made in the original publication of this letter. The error was in the calculation of the noise equivalent power (NEP) values for the avalanche photodiode detector (APD) and the superconducting single photon detector (SSPD), the incorrect values were plotted on the right axis in Fig. 1(b). The correct NEP values were calculated with the same equation reported in the original letter and the revised Fig. 1(b) is shown below. The other conclusions of the paper remain unaltered.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0003-6951	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1395
Permanent link to this record



	Author	Zinoni, C.; Alloing, B.; Li, L. H.; Marsili, F.; Fiore, A.; Lunghi, L.; Gerardino, A.; Vakhtomin, Y. B.; Smirnov, K. V.; Gol’tsman, G. N.
	Title	Single-photon experiments at telecommunication wavelengths using nanowire superconducting detectors			Type	Journal Article
	Year	2007	Publication	Appl. Phys. Lett.	Abbreviated Journal	Appl. Phys. Lett.
	Volume	91	Issue	3	Pages	031106 (1 to 3)
	Keywords	SSPD, SNSPD, APD
	Abstract	The authors report fiber-coupled superconducting single-photon detectors with specifications that exceed those of avalanche photodiodes, operating at telecommunication wavelength, in sensitivity, temporal resolution, and repetition frequency. The improved performance is demonstrated by measuring the intensity correlation function g(2)(τ) of single-photon states at 1300nm produced by single semiconductor quantum dots. This work was supported by Swiss National Foundation through the “Professeur borsier” and NCCR Quantum Photonics program, FP6 STREP “SINPHONIA” (Contract No. NMP4-CT-2005-16433), IP “QAP” (Contract No. 15848), NOE “ePIXnet,” and the Italian MIUR-FIRB program.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0003-6951	ISBN		Medium
	Area		Expedition		Conference
	Notes	Erratum: 1395			Approved	no
	Call Number				Serial	1396
Permanent link to this record



	Author	Ozhegov, R. V.; Gorshkov, K. N.; Smirnov, K. V.; Gol’tsman, G. N.; Filippenko, L. V.; Koshelets, V. P.
	Title	Terahertz imaging system based on superconducting integrated receiver			Type	Conference Article
	Year	2010	Publication	Proc. 2-nd Int. Conf. Terahertz and Microwave radiation: Generation, Detection and Applications	Abbreviated Journal	Proc. 2-nd Int. Conf. Terahertz and Microwave radiation: Generation, Detection and Applications
	Volume		Issue		Pages	20-22
	Keywords	SIS mixer, SIR
	Abstract	The development of terahertz imaging instruments for security systems is on the cutting edge of terahertz technology. We are developing a THz imaging system based on a superconducting integrated receiver (SIR). An SIR is a new type of heterodyne receiver based on an SIS mixer integrated with a flux-flow oscillator (FFO) and a harmonic mixer which is used for phase-locking the FFO. Developing an array of SIRs would allow obtaining amplitude and phase characteristics of incident radiation in the plane of the receiver. Employing an SIR in an imaging system means building an entirely new instrument with many advantages compare to traditional systems: i) high temperature resolution, comparable to the best results for incoherent receivers; ii) high spectral resolution allowing spectral analysis of various substances; iii) the local oscillator frequency can be varied to obtain images at different frequencies, effectively providing “color” images; iv) since a heterodyne receiver preserves the phase of the radiation, it is possible to construct 3D images. The paper presents a prototype THz imaging system using an 1 pixel SIR. We have studied the dependence of the noise equivalent temperature difference (NETD) on the integration time and also possible ways of achieving best possible sensitivity. An NETD of 13 mK was obtained with an integration time of 1 sec a detection bandwidth of 4 GHz at a local oscillator frequency of 520 GHz. An important advantage of an FFO is its wide operation range: 300-700 GHz.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number	ozhegov2010terahertz			Serial	1397
Permanent link to this record



	Author	Goltsman, G.
	Title	Superconducting NbN hot-electron bolometer mixer, direct detector and single-photon counter: from devices to systems			Type	Report
	Year	2009	Publication	2-nd Int. Conf. EUROFLUX	Abbreviated Journal	2-nd Int. Conf. EUROFLUX
	Volume		Issue		Pages
	Keywords	HEB, SSPD, SNSPD
	Abstract
	Address	Avignon, France
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes	Provided by the SAO/NASA Astrophysics Data System			Approved	no
	Call Number				Serial	1398
Permanent link to this record



	Author	Minaeva, O.; Divochiy, A.; Korneev, A.; Sergienko, A. V.; Goltsman, G. N.
	Title	High speed infrared photon counting with photon number resolving superconducting single-photon detectors (SSPDs)			Type	Conference Article
	Year	2009	Publication	CLEO/Europe – EQEC	Abbreviated Journal	CLEO/Europe – EQEC
	Volume		Issue		Pages
	Keywords	SSPD, SNSPD
	Abstract	A review of development and characterization of the nanostructures consisting of several meander sections, all connected in parallel was presented. Such geometry leads to a significant decrease of the kinetic inductance, without a decrease of the SSPD active area. A new type of SSPDs possess the QE of large-active- area devices, but, simultaneously, allows achieving short response times and the GHz-counting rate. This new generation of superconducting detectors has another significant advantage for quantum key distribution, they have a photon number resolving capability and can distinguish more photons.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1399
Permanent link to this record



	Author	Ozhegov, R. V.; Okunev, O. V.; Gol’tsman, G. N.; Filippenko, L. V.; Koshelets, V. P.
	Title	Noise equivalent temperature difference of a superconducting integrated terahertz receiver			Type	Journal Article
	Year	2009	Publication	J. Commun. Technol. Electron.	Abbreviated Journal	J. Commun. Technol. Electron.
	Volume	54	Issue	6	Pages	716-720
	Keywords	SIS mixer SIR NETD, FFO, harmonic mixer
	Abstract	The dependence of the noise equivalent temperature difference (NETD) of a superconducting integrated receiver (SIR) on the receiver noise temperature and the inputsignal level has been investigated. An unprecedented NETD of 13±2 mK has been measured at a SIR noise temperature of 200 K, intermediate-frequency bandwidth of 4 GHz, and time constant of 1 s. With a decrease in the input signal, an improvement in the NETD is observed. This effect is explained by a reduction in the influence of the instabilities of the receiver power supply and the amplification circuit that occur when the input signal is decreased.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1064-2269	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1400
Permanent link to this record



	Author	Baryshev, A. M.; Wild, W.; Likhachev, S. F.; Vdovin, V. F.; Goltsman, G. N.; Kardashev, N. S.
	Title	Main parameters and instrumentation of Millimetron space mission			Type	Abstract
	Year	2009	Publication	Proc. 20^th Int. Symp. Space Terahertz Technol.	Abbreviated Journal	Proc. 20th ISSTT
	Volume		Issue		Pages	108
	Keywords	SVLBI, Millimetron space observatory
	Abstract	Millimetron (official RosKosmos name ”Spectrum-M”) is a part of ambitious program called Spectrum intended to cover the whole electromagnetic spectrum with world class facilities. It is an approved mission included in Russian space program with the launch date in 2017..2019 time frame. The Millimetron satellite has a deployable 12 m diameter antenna with inner solid 4..6 m dish and a rim of petals. The mirror design is largely based on Radioastron mission concept that will be launched in 2009. If the antenna is passively cooled by radiation to open space, it would operate at approx. 50 K surface temperature, due to presence of a deployable three layer radiation screen. As a goal, there is a consideration of active cooling of antenna to 4 K, but this will depend on resources available to the project. Lagrangian libration point L2 considered for Millimetron orbit. There are four groups of scientific instruments envisioned: SVLBI instruments Space-Earth VLBI. It will allow to achieve unprecedented spatial resolution. Millimetron mission will attempt to achieve a mm/submm wave SVLBI. For that purpose, a SVLBI instrument covering selected ALMA bands and a standard VLBI band is envisioned, accompanied by a maser reference oscillator, a data digitizing and memory system, and a high speed data transmission link to ground. The ALMA bands can be extended to cover water lines if detector technology allows. Type of detector – heterodyne. Photometer/polarimeter. Recent progress in direct detector cameras with low spectral resolution, allows to propose a large format (5-10 kPixel) photometer camera on board of Millimetron mission. This camera can cover 0.1 – 2 THz region (with adequate amount of pixels per each subband). Wide band moderate resolution imaging spectrometer. Wide band moderate R = 1000 imaging spectrometer type instrument similar to SPICA SAFARI is planned, taking advantage of large cooled dish. It will cover the adequate spectral range allowable by antenna and will also work below 1 THz, as no ground instrument can have a cold main dish. High resolution spectrometer. For high resolution spectroscopy a heterodyne instrument is proposed, conceptually similar to HIFI on Herschel. This instrument will cover interesting frequency spots in 0.5..4 THz frequency range (using central part of antenna for higher frequency). It is sure that advances in LO and mixer technology will allow this frequency coverage.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1401
Permanent link to this record



	Author	Wild, W.; Kardashev, N. S.; Likhachev, S. F.; Babakin, N. G.; Arkhipov, V. Y.; Vinogradov, I. S.; Andreyanov, V. V.; Fedorchuk, S. D.; Myshonkova, N. V.; Alexsandrov, Y. A.; Novokov, I. D.; Goltsman, G. N.; Cherepaschuk, A. M.; Shustov, B. M.; Vystavkin, A. N.; Koshelets, V. P.; Vdovin, V.F.; de Graauw, T.; Helmich, F.; vd Tak, F.; Shipman, R.; Baryshev, A.; Gao, J. R.; Khosropanah, P.; Roelfsema, P.; Barthel, P.; Spaans, M.; Mendez, M.; Klapwijk, T.; Israel, F.; Hogerheijde, M.; vd Werf, P.; Cernicharo, J.; Martin-Pintado, J.; Planesas, P.; Gallego, J. D.; Beaudin, G.; Krieg, J. M.; Gerin, M.; Pagani, L.; Saraceno, P.; Di Giorgio, A. M.; Cerulli, R.; Orfei, R.; Spinoglio, L.; Piazzo, L.; Liseau, R.; Belitsky, V.; Cherednichenko, S.; Poglitsch, A.; Raab, W.; Guesten, R.; Klein, B.; Stutzki, J.; Honingh, N.; Benz, A.; Murphy, A.; Trappe, N.; Räisänen, A.
	Title	Millimetron—a large Russian-European submillimeter space observatory			Type	Journal Article
	Year	2009	Publication	Exp. Astron.	Abbreviated Journal	Exp. Astron.
	Volume	23	Issue	1	Pages	221-244
	Keywords	Millimetron space observatory, VLBI, very long baseline interferometry
	Abstract	Millimetron is a Russian-led 12 m diameter submillimeter and far-infrared space observatory which is included in the Space Plan of the Russian Federation for launch around 2017. With its large collecting area and state-of-the-art receivers, it will enable unique science and allow at least one order of magnitude improvement with respect to the Herschel Space Observatory. Millimetron will be operated in two basic observing modes: as a single-dish observatory, and as an element of a ground-space very long baseline interferometry (VLBI) system. As single-dish, angular resolutions on the order of 3 to 12 arc sec will be achieved and spectral resolutions of up to a million employing heterodyne techniques. As VLBI antenna, the chosen elliptical orbit will provide extremely large VLBI baselines (beyond 300,000 km) resulting in micro-arc second angular resolution.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0922-6435	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1402
Permanent link to this record



	Author	Goltsman, G. N.
	Title	Ultrafast nanowire superconducting single-photon detector with photon number resolving capability			Type	Conference Article
	Year	2009	Publication	Proc. SPIE	Abbreviated Journal	Proc. SPIE
	Volume	7236	Issue		Pages	72360D (1 to 11)
	Keywords	PNR NbN SSPD, SNSPD, superconducting single-photon detectors, photon number resolving detectors, ultrathin NbN films
	Abstract	In this paper we present a review of the state-of-the-art superconducting single-photon detector (SSPD), its characterization and applications. We also present here the next step in the development of SSPD, i.e. photon-number resolving SSPD which simultaneously features GHz counting rate. We have demonstrated resolution up to 4 photons with quantum efficiency of 2.5% and 300 ps response pulse duration providing very short dead time.
	Address
	Corporate Author				Thesis
	Publisher	SPIE	Place of Publication		Editor	Arakawa, Y.; Sasaki, M.; Sotobayashi, H.
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1403
Permanent link to this record



	Author	Tikhonov, V. V.; Polyakova, O. N.; Gol’tsman, G. N.; Dzardanov, A. L.; Boyarskiy, D. A.
	Title	Determination of dielectric properties of ore minerals in the microwave band			Type	Journal Article
	Year	2008	Publication	Radiophys. Quant. Electron.	Abbreviated Journal	Radiophys. Quant. Electron.
	Volume	51	Issue	12	Pages	966-974
	Keywords	ore complex permittivity, chalcopyrite, magnetite, sphalerite, labradorite
	Abstract	We consider a method for determining the complex dielectric permittivity of ore and nonmetal minerals in the microwave band of electromagnetic radiation. The results of measuring the reflectivity and transmittivity of chalcopyrite, magnetite, sphalerite, and labradorite samples in the frequency range 77–300 GHz are presented. A method for calculation of the complex dielectric permittivity of minerals on the basis of the obtained experimental data is proposed. The approximation formulas for calculation of the complex dielectric permittivity of the studied minerals are given.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0033-8443	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1404
Permanent link to this record



	Author	Smirnov, K. V.; Vachtomin, Y. B.; Ozhegov, R. V.; Pentin, I. V.; Slivinskaya, E. V.; Korneev, A. A.; Goltsman, G. N.
	Title	Fiber coupled single photon receivers based on superconducting detectors for quantum communications and quantum cryptography			Type	Conference Article
	Year	2008	Publication	Proc. SPIE	Abbreviated Journal	Proc. SPIE
	Volume	7138	Issue		Pages	713827 (1 to 6)
	Keywords	SSPD, SNSPD, superconducting single photon detector, ultra-thin superconducting films, optical fiber coupling, ready to use receiver
	Abstract	At present superconducting detectors become increasingly attractive for various practical applications. In this paper we present results on the depelopment of fiber coupled receiver systems for the registration of IR single photons, optimized for telecommunication and quantum-cryptography. These receiver systems were developed on the basis of superconducting single photon detectors (SSPD) of VIS and IR wavelength ranges. The core of the SSPD is a narrow ( 100 nm) and long ( 0,5 mm) strip in the form of a meander which is patterned from a 4-nm-thick NbN film (T_C=10-11 K, j_C= 5-7â€¢10⁶ A/cm²); the sensitive area dimensions are 10Ã—10 Î¼m². The main problem to be solved while the receiver system development was optical coupling of a single-mode fiber (9 microns in diameter) with the SSPD sensitive area. Characteristics of the developed system at the optical input are as follows: quantum efficiency >10 % (at 1.3 Î¼m), >4 % (at 1.55 Î¼m); dark counts rate â‰¤1 s^-1; duration of voltage pulse â‰¤5 ns; jitter â‰¤40 ps. The receiver systems have either one or two identical channels (for the case of carrying out correlation measurements) and are made as an insert in a helium storage Dewar.
	Address
	Corporate Author				Thesis
	Publisher	Spie	Place of Publication		Editor	Tománek, P.; Senderáková, D.; Hrabovský, M.
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1405
Permanent link to this record



	Author	Polyakova, O. N.; Tikhonov, V. V.; Dzardanov, A. L.; Boyarskii, D. A.; Gol’tsman, G. N.
	Title	Dielectric characteristics of ore minerals in a 10–40 GHz frequency range			Type	Journal Article
	Year	2008	Publication	Tech. Phys. Lett.	Abbreviated Journal	Tech. Phys. Lett.
	Volume	34	Issue	11	Pages	967-970
	Keywords	ore minerals, complex permittivity, sphalerite, magnetite, labradorite
	Abstract	A new approach to investigation of the complex dielectric permittivity of both nonmetallic and ore minerals in the microwave frequency range is proposed. Using this approach, data on the complex permittivity of sphalerite, magnetite, and labradorite in a 10–40 GHz frequency range have been obtained for the first time. A method is proposed for calculating the complex permittivity from experimentally measured frequency dependences of the reflection and transmission coefficients of a plane-parallel plate of a given mineral. Approximate expressions that can be used for calculations of the complex refractive index and permittivity of minerals are presented.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1063-7850	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1406
Permanent link to this record



	Author	Mohan, N.; Minaeva, O.; Gol'tsman, G. N.; Nasr, M. B.; Saleh, B. E.; Sergienko, A. V.; Teich, M. C.
	Title	Photon-counting optical coherence-domain reflectometry using superconducting single-photon detectors			Type	Journal Article
	Year	2008	Publication	Opt. Express	Abbreviated Journal	Opt. Express
	Volume	16	Issue	22	Pages	18118-18130
	Keywords	SSPD, SNSPD
	Abstract	We consider the use of single-photon counting detectors in coherence-domain imaging. Detectors operated in this mode exhibit reduced noise, which leads to increased sensitivity for weak light sources and weakly reflecting samples. In particular, we experimentally demonstrate the possibility of using superconducting single-photon detectors (SSPDs) for optical coherence-domain reflectometry (OCDR). These detectors are sensitive over the full spectral range that is useful for carrying out such imaging in biological samples. With counting rates as high as 100 MHz, SSPDs also offer a high rate of data acquisition if the light flux is sufficient.
	Address	Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA. nm82@bu.edu
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1094-4087	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:18958090			Approved	no
	Call Number				Serial	1407
Permanent link to this record



	Author	Nasr, M. B.; Minaeva, O.; Goltsman, G. N.; Sergienko, A. V.; Saleh, B. E.; Teich, M. C.
	Title	Submicron axial resolution in an ultrabroadband two-photon interferometer using superconducting single-photon detectors			Type	Journal Article
	Year	2008	Publication	Opt. Express	Abbreviated Journal	Opt. Express
	Volume	16	Issue	19	Pages	15104-15108
	Keywords	SSPD, SNSPD
	Abstract	We generate ultrabroadband biphotons via the process of spontaneous parametric down-conversion in a quasi-phase-matched nonlinear grating that has a linearly chirped poling period. Using these biphotons in conjunction with superconducting single-photon detectors (SSPDs), we measure the narrowest Hong-Ou-Mandel dip to date in a two-photon interferometer, having a full width at half maximum (FWHM) of approximately 5.7 fsec. This FWHM corresponds to a quantum optical coherence tomography (QOCT) axial resolution of 0.85 µm. Our results indicate that a high flux of nonoverlapping biphotons may be generated, as required in many applications of nonclassical light.
	Address	Departments of Electrical & Computer Engineering and Physics, Quantum Imaging Laboratory, Boston University, Boston, MA 02215, USA. boshra@bu.edu
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language	English	Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1094-4087	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:18795048			Approved	no
	Call Number				Serial	1408
Permanent link to this record



	Author	Sáysz, Wojciech; Guziewicz, Marek; Bar, Jan; Wegrzecki, Maciej; Grabiec, Piotr; Grodecki, Remigiusz; Wegrzecka, Iwona; Zwiller, Val; Milosnaya, Irina; Voronov, Boris; Gol’tsman, Gregory; Kitaygorsky, Jen; Sobolewski, Roman
	Title	Superconducting NbN nanostructures for single photon quantum detectors			Type	Abstract
	Year	2008	Publication	Proc. 7-th Int. Conf. Ion Implantation and Other Applications of Ions and Electrons	Abbreviated Journal	Proc. 7-th Int. Conf. Ion Implantation and Other Applications of Ions and Electrons
	Volume		Issue		Pages	160
	Keywords	SSPD, SNSPD
	Abstract	Practical quantum systems such as quantum communication (QC) or quantum measurement systems require detectors with high speed, high sensitivity, high quantum efficiency (QE), and short deadtimes along with precise timing characteristics and low dark counts. Superconducting single photon detectors (SSPDs) based on ultrathin meander type NbN nanostripes (operated at T=2-5K) are a new and highly promising type of devices fulfilling above requirements. In this paper we present results of the SSPDs nanostructure technological optimization. The base for our detector is thin-film (4nm) NbN layer deposited on 350- P m-thick sapphire substrate The active element of the detector is a meander- nanostructure made of 4-nm-thick and 100-nm-wide NbN stripe, covering 10 u 10 P m 2 area with the filling factor ~0,5. The NbN superconducting films were deposited on sapphire substrates by DC reactive magnetron sputtering whereas the meander element of the detector was patterned by the direct electron-beam lithography followed by reactive-ion etching. To enhance the SSPD efficiency at Ȝ = 1.55 P m, we have performed an approach to increase the absorption of the detector by integrating it with optical resonant cavity. An optical microcavity optimized for absorption of 1.55 P m photons was designed as an one-mirror resonator consisting of a Ȝ/4 dielectric layer and a metallic mirror. The microcavity was deposited on the top of the NbN SSPD meander. The resonator was formed by the dielectric SiO 2 layer and metal mirror made of gold or palladium. Microcavity layers were deposited using a magnetron sputtering system.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1409
Permanent link to this record



	Author	de Lara, D. Perez; Ejrnaes, M.; Casaburi, A.; Lisitskiy, M.; Cristiano, R.; Pagano, S.; Gaggero, A.; Leoni, R.; Golt’sman, G.; Voronov, B.
	Title	Feasibility investigation of NbN nanowires as detector in time-of-flight mass spectrometers for macromolecules of interest in biology (proteins)			Type	Journal Article
	Year	2008	Publication	J. Low Temp. Phys.	Abbreviated Journal	J. Low Temp. Phys.
	Volume	151	Issue	3-4	Pages	771-776
	Keywords	NbN SSPD, SNSPD, nanowires
	Abstract	We are investigating the possibility of using NbN nanowires as detectors in time-of-flight mass spectrometers for investigation of macromolecules of interest in biology (proteins). NbN nanowires could overcome the two major drawbacks encountered so far by cryogenic detectors, namely the low working temperature in the mK region and the slow temporal response. In fact, NbN nanowires can work at 5 K and the response time is at least a factor 10–100 better than that of other cryogenic detectors. We present a feasibility study based on a numerical code to calculate the response of a NbN nanowire. The parameter space is investigated at different energies from IR to macromolecules (i.e. from eV to keV) in order to understand if larger value of film thickness and width can be used for the keV energy region. We also present preliminary experimental results of irradiation with X-ray photons of NbN to simulate the effect of macromolecules of the same energy.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0022-2291	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1410
Permanent link to this record



	Author	Cherednichenko, S.; Drakinskiy, V.; Lecomte, B.; Dauplay, F.; Krieg, J.-M.; Delorme, Y.; Feret, A.; Hübers, H.-W.; Semenov, A.D.; Gol’tsman, G.N.
	Title	Terahertz heterodyne array based on NbN HEB mixers			Type	Abstract
	Year	2008	Publication	Proc. 19^th Int. Symp. Space Terahertz Technol.	Abbreviated Journal
	Volume		Issue		Pages	43
	Keywords	NbN HEB mixers array
	Abstract	A 16 pixel heterodyne receiver for 2.5 THz is been developed based on NbN superconducting hot-electron bolometer (HEB) mixers. The receiver uses a quasioptical RF coupling approach where HEB mixers are integrated into double dipole antennas on 1.5μm thick Si3N4 / SiO2 membranes. Miniature mirrors (one per pixel) and back short for the antenna were used to design the output mixer beam profile. The camera design allows all 16 pixel IF readout in parallel. The gain bandwidth of the HEB mixers on Si3N4 / SiO 2 membranes was found to be about 3 GHz, when an MgO buffer layers is applied on the membrane. We will also present the progress in the camera heterodyne tests.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1411
Permanent link to this record



	Author	Wild, Wolfgang; Baryshev, Andrey; de Graauw, Thijs; Kardashev, Nikolay; Likhachev, Sergey; Goltsman, Gregory; Koshelets, Valery
	Title	Instrumentation for Millimetron – a large space antenna for THz astronomy			Type	Conference Article
	Year	2008	Publication	Proc. 19^th Int. Symp. Space Terahertz Technol.	Abbreviated Journal	Proc. 19^th Int. Symp. Space Terahertz Technol.
	Volume		Issue		Pages	186-191
	Keywords	Millimetron space observatory, VLBI
	Abstract	Millimetron is a Russian-led 12m diameter submillimeter and far-infrared space observatory which is included in the Space Plan of the Russian Federation and funded for launch after 2015. With its large collecting area and state-of-the-art receivers, it will enable unique science and allow at least one order of magnitude improvement with respect to the Herschel Space Observatory. Millimetron is currently in a conceptual design phase carried out by the Astro Space Center in Moscow and SRON Netherlands Institute for Space Research. It will use a passively cooled deployable antenna with a high-precision central 3.5m diameter mirror and high- precision antenna petals. The antenna is specified for observations up to ~2 THz over the whole 12m diameter, and to higher frequencies using the central 3.5m solid mirror. Millimetron will be operated in two basic observing modes: as a single-dish observatory, and as an element of a ground-space VLBI system. As single-dish, angular resolutions on the order of 3 to 12 arcsec will be achieved and spectral resolutions of up to 10 6 employing heterodyne techniques. As VLBI antenna, the chosen elliptical orbit will provide extremely large VLBI baselines resulting in micro-arcsec angular resolution. The scientific payload will consist of heterodyne and direct detection instruments covering the most important sub-/millimeter spectral regions (including some ALMA bands) and will build on the Herschel and ALMA heritage.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1412
Permanent link to this record



	Author	Okunev, O.; Chulkova, G.; Milostnaya, I.; Antipov, A.; Smirnov, K.; Morozov, D.; Korneev, A.; Voronov, B.; Gol’tsman, G.; Slysz, W.; Wegrzecki, M.; Bar, J.; Grabiec, P.; Górska, M.; Pearlman, A.; Cross, A.; Kitaygorsky, J.; Sobolewski, R.
	Title	Registration of infrared single photons by a two-channel receiver based on fiber-coupled superconducting single-photon detectors			Type	Conference Article
	Year	2008	Publication	Proc. SPIE	Abbreviated Journal	Proc. SPIE
	Volume	7009	Issue		Pages	70090V (1 to 8)
	Keywords	SSPD, SNSPD, single-photon detectors, superconductors, superconducting nanost
	Abstract	Single-photon detectors (SPDs) are the foundation of all quantum communications (QC) protocols. Among different classes of SPDs currently studied, NbN superconducting SPDs (SSPDs) are established as the best devices for ultrafast counting of single photons in the infrared (IR) wavelength range. The SSPDs are nanostructured, 100 Î¼m² in total area, superconducting meanders, patterned by electron lithography in ultra-thin NbN films. Their operation has been explained within a phenomenological hot-electron photoresponse model. We present the design and performance of a novel, two-channel SPD receiver, based on two fiber-coupled NbN SSPDs. The receivers have been developed for fiber-based QC systems, operational at 1.3 Î¼m and 1.55 Î¼m telecommunication wavelengths. They operate in the temperature range from 4.2 K to 2 K, in which the NbN SSPDs exhibit their best performance. The receiver unit has been designed as a cryostat insert, placed inside a standard liquid-heliumstorage dewar. The input of the receiver consists of a pair of single-mode optical fibers, equipped with the standard FC connectors and kept at room temperature. Coupling between the SSPD and the fiber is achieved using a specially designed, precise micromechanical holder that places the fiber directly on top of the SSPD nanostructure. Our receivers achieve the quantum efficiency of up to 7% for near-IR photons, with the coupling efficiency of about 30%. The response time was measured to be < 1.5 ns and it was limited by our read-out electronics. The jitter of fiber-coupled SSPDs is < 35 ps and their dark-count rate is below 1s^-1. The presented performance parameters show that our single-photon receivers are fully applicable for quantum correlation-type QC systems, including practical quantum cryptography.
	Address
	Corporate Author				Thesis
	Publisher	SPIE	Place of Publication		Editor	Sukhoivanov, I.A.; Svich, V.A.; Shmaliy, Y.S.
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1413
Permanent link to this record



	Author	Jukna, A.; Kitaygorsky, J.; Pan, D.; Cross, A.; Perlman, A.; Komissarov, I.; Sobolewski, R.; Okunev, O.; Smirnov, K.; Korneev, A.; Chulkova, G.; Milostnaya, I.; Voronov, B.; Gol'tsman, G.
	Title	Dynamics of hotspot formation in nanostructured superconducting stripes excited with single photons			Type	Journal Article
	Year	2008	Publication	Acta Physica Polonica A	Abbreviated Journal	Acta Physica Polonica A
	Volume	113	Issue	3	Pages	955-958
	Keywords	SSPD, SNSPD
	Abstract	Dynamics of a resistive hotspot formation by near-infrared-wavelength single photons in nanowire-type superconducting NbN stripes was investigated. Numerical simulations of ultrafast thermalization of photon-excited nonequilibrium quasiparticles, their multiplication and out-diffusion from a site of the photon absorption demonstrate that 1.55 μm wavelength photons create in an ultrathin, two-dimensional superconducting film a resistive hotspot with the diameter which depends on the photon energy, and the nanowire temperature and biasing conditions. Our hotspot model indicates that under the subcritical current bias of the 2D stripe, the electric field penetrates the superconductor at the hotspot boundary, leading to suppression of the stripe superconducting properties and accelerated development of a voltage transient across the stripe.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1414
Permanent link to this record



	Author	Zhang, W.; Li, N.; Jiang, L.; Ren, Y.; Yao, Q.-J.; Lin, Z.-H.; Shi, S.-C.; Voronov, B. M.; Gol’tsman, G. N.
	Title	Dependence of noise temperature of quasi-optical superconducting hot-electron bolometer mixers on bath temperature and optical-axis displacement			Type	Conference Article
	Year	2008	Publication	Proc. SPIE	Abbreviated Journal	Proc. SPIE
	Volume	6840	Issue		Pages	684007 (1 to 8)
	Keywords	NbN HEB mixers, noise temperature, LO power
	Abstract	It is known that the increase of bath temperature results in the decrease of critical current of superconducting hot-electron bolometer (HEB) mixers owing to the depression of superconductivity, thus leading to the degradation of the mixer’s sensitivity. Here we report our study on the effect of bath temperature on the heterodyne mixing performance of quasi-optical superconducting NbN HEB mixers incorporated with a two-arm log-spiral antenna. The correlation between the bath temperature, critical current, LO power requirement and noise temperature is investigated at 0.5 THz. Furthermore, the heterodyne mixing performance of quasi-optical superconducting NbN HEB mixers is examined while there is an optical-axis displacement between the center of the extended hemispherical silicon lens and the superconducting NbN HEB device, which is placed on the back of the lens. Detailed experimental results and analysis are presented.
	Address
	Corporate Author				Thesis
	Publisher	Spie	Place of Publication		Editor	Zhang, C.; Zhang, X.-C.
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference	Terahertz Photonics
	Notes				Approved	no
	Call Number				Serial	1415
Permanent link to this record



	Author	Casaburi, A.; Ejrnaes, M.; Quaranta, O.; Gaggero, A.; Mattioli, F.; Leoni, R.; Voronov, B.; Gol'tsman, G.; Lisitskiy, M.; Esposito, E.; Nappi, C.; Cristiano, R.; Pagano, S.
	Title	Experimental characterization of NbN nanowire optical detectors with parallel stripline configuration			Type	Conference Article
	Year	2008	Publication	J. Phys.: Conf. Ser.	Abbreviated Journal	J. Phys.: Conf. Ser.
	Volume	97	Issue		Pages	012265 (1 to 6)
	Keywords	NbN SSPD, SNSPD
	Abstract	We have developed a novel geometrical configuration for NbN-based superconducting single photon optical detector (SSPD) that achieves two goals: a much lower intrinsic impedance, and a consequently greater bandwidth, and a much larger signal amplitude compared to the standard meandered configuration. This has been obtained by implementing a properly designed parallel stripline structure where a cascade switching mechanism occurs when one of the striplines is hit by an optical photon. The overall switching occurs synchronously and in a very short time, giving rise to a strong and fast voltage pulse. The SSPD have been realized using state of the art NbN deposition technology and e-beam lithography. The strips are 100 nm wide and 5 μm long and have been realized with 4 nm NbN film on sapphire and Si substrate. We report on experimental characterization of such novel devices. The performances of the proposed novel type of SSPD are compared with standard SSPD design and results in terms of signal amplitude, risetime and effective detection area.
	Address
	Corporate Author				Thesis
	Publisher	IOP Publishing	Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1742-6596	ISBN		Medium
	Area		Expedition		Conference	8th European Conference on Applied Superconductivity (EUCAS 2007)
	Notes				Approved	no
	Call Number				Serial	1416
Permanent link to this record



	Author	Chen, J.; Kang, L.; Jin, B. B.; Xu, W. W.; Wu, P. H.; Zhang, W.; Jiang, L.; Li, N.; Shi, S. C.; Gol'tsman, G. N.
	Title	Properties of terahertz superconducting hot electron bolometer mixers			Type	Journal Article
	Year	2008	Publication	Int. J. Terahertz Sci. Technol.	Abbreviated Journal	Int. J. Terahertz Sci. Technol.
	Volume	1	Issue	1	Pages	37-41
	Keywords	NbN HEB mixers, noise temperature
	Abstract	A quasi-optical superconducting niobium nitride (NbN) hot electron bolometer (HEB) mixer has been fabricated and measured in the terahertz (THz) frequency range of 0.5~2.52 THz. A receiver noise temperature of 2000 K at 2.52 THz has been obtained for the mixer without corrections. Also, the effect of a Parylene C anti-reflection (AR) coating on the silicon (Si) lens has been studied.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1417
Permanent link to this record



	Author	Ejrnaes, M.; Cristiano, R.; Quaranta, O.; Pagano, S.; Gaggero, A.; Mattioli, F.; Leoni, R.; Voronov, B.; Gol’tsman, G.
	Title	A cascade switching superconducting single photon detector			Type	Journal Article
	Year	2007	Publication	Appl. Phys. Lett.	Abbreviated Journal	Appl. Phys. Lett.
	Volume	91	Issue	26	Pages	262509 (1 to 3)
	Keywords	SSPD, SNSPD, parallel-wire
	Abstract	We have realized superconducting single photon detectors with reduced inductance and increased signal pulse amplitude. The detectors are based on a parallel connection of ultrathin NbN nanowires with a common bias inductance. When properly biased, an absorbed photon induces a cascade switch of all the parallel wires generating a signal pulse amplitude of 2mV. The parallel wire configuration lowers the detector inductance and reduces the response time well below 1ns. This work was performed in the framework of the EU project “SINPHONIA” NMP4-CT-2005-016433.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0003-6951	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1418
Permanent link to this record



	Author	Cherednichenko, S.; Drakinskiy, V.; Baubert, J.; Lecomte, B.; Dauplay, F.; Krieg, J.-M.; Delorme, Y.; Feret, A.; Hübers, H.-W.; Semenov, A. D.; Gol’tsman, G. N.
	Title	2.5 THz multipixel heterodyne receiver based on NbN HEB mixers			Type	Abstract
	Year	2007	Publication	Proc. 18^th Int. Symp. Space Terahertz Technol.	Abbreviated Journal	Proc. 18^th Int. Symp. Space Terahertz Technol.
	Volume		Issue		Pages	112
	Keywords	NbN HEB mixers
	Abstract	A 16 pixel heterodyne receiver for 2.5 THz has been developed based on NbN superconducting hot-electron bolometer (HEB) mixers. The receiver uses a quasioptical RF coupling approach where HEB mixers are integrated into double dipole antennas on 1.5μm thick Si3N4 / SiO2 membranes. Spherical mirrors (one per pixel) and backshort distance from the antenna have been used to design the output mixer beam profile. The camera design allows all 16 pixel IF readout in parallel. Measurements of the mixers sensitivity and the input RF band are presented, and compared against calculations.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1419
Permanent link to this record



	Author	Semenov, A.; Richter, H.; Smirnov, A.; Günther, B.; Hübers, H.-W.; Il’in, K.; Siegel, M.; Gol’tsman, G.; Drakinskiy, V.; Merkel, H.; Karamarkovic, J.
	Title	Development of HEB mixers for GREAT and for security screening			Type	Abstract
	Year	2007	Publication	Proc. 18^th Int. Symp. Space Terahertz Technol.	Abbreviated Journal	Proc. 18^th Int. Symp. Space Terahertz Technol.
	Volume		Issue		Pages	184
	Keywords	NbN HEB mixers, GREAT
	Abstract	We report the study on the quasioptical coupling efficiency and the gain bandwidth of NbN hot-electron bolometer mixers developed for the 4.7 THz channel of the German receiver for Astronomy at THz-frequencies (GREAT) and for security screening at subterahertz frequencies. Radiation coupling efficiency and directive properties of integrated lens antennas with log-spiral, log-periodic and double-slot planar feeds coupled to a hot-electron bolometer were experimentally studied at frequencies from 1 THz to 6 THz and compared with simulations based on the method of moments and the physical-optics ray tracing. For all studied antennas the modeled spectral dependence of the coupling efficiency fits to the experimental data obtained with both Fourier transform spectroscopy and noise temperature measurements only if the complex impedance of the bolometer is explicitly taken into account. Our experimental data did not indicate any noticeable contribution of the quantum noise to the system noise temperature. The experimentally observed deviation of the beam pattern from the model prediction increases with frequency and is most likely due to a non- ideality of the presently used lenses. Study of the intermediate frequency mixer gain at local oscillator (LO) frequencies between 2.5 THz and 0.3 THz showed an increase of the gain bandwidth at low LO frequencies that was understood as the contribution of the direct interaction of magnetic vortices with the radiation field. We have found that the non- homogeneous hot-spot model more adequately describes variation of the intermediate frequency bandwidth with the applied local oscillator power than any of uniform mixer models. The state-of-the-day performance of the GREAT 4.7-THz channel and the 0.8-THz security scanner will be presented.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1420
Permanent link to this record



	Author	Ryabchun, Sergey; Tong, Cheuk-yu Edward; Blundell, Raymond; Kimberk, Robert; Gol’tsman, Gregory
	Title	Stabilisation of a terahertz hot-electron bolometer mixer with microwave feedback control			Type	Conference Article
	Year	2007	Publication	Proc. 18^th Int. Symp. Space Terahertz Technol.	Abbreviated Journal	Proc. 18^th Int. Symp. Space Terahertz Technol.
	Volume		Issue		Pages	193-198
	Keywords	waveguide NbN HEB mixers, Allan variance, stability
	Abstract	We report on implementation of microwave feedback control loop to stabilise the performance of an HEB mixer receiver. It is shown that the receiver sensitivity increases by a factor of 4 over a 16-minute scan, and the corresponding Allan time increases up to 10 seconds, as opposed to an open loop value of 1 second. Our experiments also demonstrate that the receiver sensitivity is limited by the intermediate frequency chain.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1421
Permanent link to this record



	Author	Gol’tsman, G. N.
	Title	The “Millimetron” project, a future space telescope mission			Type	Abstract
	Year	2007	Publication	Proc. 18^th Int. Symp. Space Terahertz Technol.	Abbreviated Journal	Proc. 18^th Int. Symp. Space Terahertz Technol.
	Volume		Issue		Pages	255
	Keywords	Millimetron space observatory, VLBI
	Abstract	The goal of the Millimetron project is to develop a space observatory operating in the millimeter, sub-millimeter and infrared wavelength ranges using a 12-m actively cooled telescope in a single-dish mode and as an interferometer with the space-ground and space-space baselines (the later after the launch of the second identical space telescope). The Millimetron’s main reflector and other optics will be cooled down to 4K thus enabling astronomical observations with super high sensitivity in MM and subMM (down to nanoJansky level). Heterodyne observations in an interferometer mode at frequencies 0.1-1 THz will provide super high angular resolution. The main instruments, planned to be installed are wide-range imaging arrays, radiometers with spectrometers and polarimeters, VLBI heterodyne receivers, and Mikelson type interferometer devices. Wide-range MM and subMM imaging arrays and spectrometers will be based on a superconducting hot electron direct detectors with Andreev mirrors operating at 0.1 K. Such detectors are the best candidates to reach the noise equivalent power level of 10 -19 -10 -20 W/√Hz. Heterodyne receivers will be both SIS based superconducting integrated receiver with flux-flow oscillator as LO (0.1-0.9 THz range) and HEB based receivers using multiplied Gunn oscillator as LO for 1-2 THz range and quantum cascade lasers as LO for 2-5 THz range. For observations in middle IR region there will be installed large arrays of superconducting single photon detectors, providing imaging with very high dynamic range and ultimate sensitivity.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1422
Permanent link to this record



	Author	Bell, M.; Sergeev, A.; Mitin, V.; Bird, J.; Verevkin, A.; Gol’tsman, G.
	Title	One-dimensional resistive states in quasi-two-dimensional superconductors: Experiment and theory			Type	Journal Article
	Year	2007	Publication	Phys. Rev. B	Abbreviated Journal	Phys. Rev. B
	Volume	76	Issue	9	Pages	094521 (1 to 5)
	Keywords	uasi-two-dimensional superconductors, NbN
	Abstract	We investigate competition between one- and two-dimensional topological excitations—phase slips and vortices—in the formation of resistive states in quasi-two-dimensional superconductors in a wide temperature range below the mean-field transition temperature TC0. The widths w=100nm of our ultrathin NbN samples are substantially larger than the Ginzburg-Landau coherence length ξ=4nm, and the fluctuation resistivity above TC0 has a two-dimensional character. However, our data show that the resistivity below TC0 is produced by one-dimensional excitations—thermally activated phase slip strips (PSSs) overlapping the sample cross section. We also determine the scaling phase diagram, which shows that even in wider samples the PSS contribution dominates over vortices in a substantial region of current and/or temperature variations. Measuring the resistivity within 7 orders of magnitude, we find that the quantum phase slips can only be essential below this level.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1098-0121	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1423
Permanent link to this record



	Author	Reiger, E.; Pan, D.; Slysz, W.; Jukna, A.; Sobolewski, R.; Dorenbos, S.; Zwiller, V.; Korneev, A.; Chulkova, G.; Milostnaya, I.; Minaeva, O.; Gol'tsman, G.; Kitaygorsky, J.
	Title	Spectroscopy with nanostructured superconducting single photon detectors			Type	Journal Article
	Year	2007	Publication	IEEE J. Select. Topics Quantum Electron.	Abbreviated Journal	IEEE J. Select. Topics Quantum Electron.
	Volume	13	Issue	4	Pages	934-943
	Keywords	SSPD, SNSPD
	Abstract	Superconducting single-photon detectors (SSPDs) are nanostructured devices made from ultrathin superconducting films. They are typically operated at liquid helium temperature and exhibit high detection efficiency, in combination with very low dark counts, fast response time, and extremely low timing jitter, within a broad wavelength range from ultraviolet to mid-infrared (up to 6 mu m). SSPDs are very attractive for applications such as fiber-based telecommunication, where single-photon sensitivity and high photon-counting rates are required. We review the current state-of-the-art in the SSPD research and development, and compare the SSPD performance to the best semiconducting avalanche photodiodes and other superconducting photon detectors. Furthermore, we demonstrate that SSPDs can also be successfully implemented in photon-energy-resolving experiments. Our approach is based on the fact that the size of the hotspot, a nonsuperconducting region generated upon photon absorption, is linearly dependent on the photon energy. We introduce a statistical method, where, by measuring the SSPD system detection efficiency at different bias currents, we are able to resolve the wavelength of the incident photons with a resolution of 50 nm.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1077-260X	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1424
Permanent link to this record



	Author	Gao, J. R.; Hajenius, M.; Tichelaar, F. D.; Klapwijk, T. M.; Voronov, B.; Grishin, E.; Gol’tsman, G.; Zorman, C. A.; Mehregany, M.
	Title	Monocrystalline NbN nanofilms on a 3C-SiC∕Si substrate			Type	Journal Article
	Year	2007	Publication	Appl. Phys. Lett.	Abbreviated Journal	Appl. Phys. Lett.
	Volume	91	Issue	6	Pages	062504 (1 to 3)
	Keywords	NbN films, nanofilms
	Abstract	The authors have realized NbN (100) nanofilms on a 3C-SiC (100)/Si(100) substrate by dc reactive magnetron sputtering at 800°C. High-resolution transmission electron microscopy (HRTEM) is used to characterize the films, showing a monocrystalline structure and confirming epitaxial growth on the 3C-SiC layer. A film ranging in thickness from 3.4to4.1nm shows a superconducting transition temperature of 11.8K, which is the highest reported for NbN films of comparable thickness. The NbN nano-films on 3C-SiC offer a promising alternative to improve terahertz detectors. For comparison, NbN nanofilms grown directly on Si substrates are also studied by HRTEM. The authors acknowledge S. V. Svetchnikov at National Centre for HRTEM at Delft, who prepared the specimens for HRTEM inspections. This work was supported by the EU through RadioNet and INTAS.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0003-6951	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1425
Permanent link to this record



	Author	Hajenius, M.; Yang, Z. Q.; Gao, J. R.; Baselmans, J. J. A.; Klapwijk, T. M.; Voronov, B.; Gol'tsman, G.
	Title	Optimized sensitivity of NbN hot electron bolometer mixers by annealing			Type	Journal Article
	Year	2007	Publication	IEEE Trans. Appl. Supercond.	Abbreviated Journal	IEEE Trans. Appl. Supercond.
	Volume	17	Issue	2	Pages	399-402
	Keywords	NbN HEB mixers
	Abstract	We report that the heterodyne sensitivity of superconducting hot-electron bolometers (HEBs) increases by 25-30% after annealing at 85degC in high vacuum. The devices studied are twin-slot antenna coupled mixers with a small area NbN bridge of 1 mum times 0.15 mum, above which there is a SiO 2 passivation layer. The mixer noise temperature, gain, and resistance versus temperature curve of a HEB before and after annealing are compared and analysed. We show that the annealing reduces the intrinsic noise of the mixer by 37% and makes the superconducting transition of the bridge and the contacts sharper. We argue that the reduction ofthe noise is mainly due to the improvement of the transparency of the contact/film interface. The lowest receiver noise temperature of 700 K is measured at a local oscillator frequency of 1.63 THz and at a bath temperature of 4.2 K.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1051-8223	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1426
Permanent link to this record



	Author	Ryabchun, S.; Tong, C.-Y. E.; Blundell, R.; Kimberk, R.; Gol'tsman, G.
	Title	Study of the effect of microwave radiation on the operation of HEB mixers in the terahertz frequency range			Type	Journal Article
	Year	2007	Publication	IEEE Trans. Appl. Supercond.	Abbreviated Journal	IEEE Trans. Appl. Supercond.
	Volume	17	Issue	2	Pages	391-394
	Keywords	NbN HEB mixers
	Abstract	We have investigated the effect of injecting microwave radiation, with a frequency much lower than that corresponding to the energy gap of the superconductor, on the performance of the hot-electron bolometer mixer incorporated into a THz heterodyne receiver. More specifically, we show that exposing the mixer to microwave radiation does not cause a significant rise of the receiver noise temperature and fall of the mixer conversion gain so long as the microwave power is a small fraction of local oscillator power. The injection of a small, but controlled amount of microwave power therefore enables active compensation of local oscillator power and coupling fluctuations which can significantly degrade the gain stability of hot electron bolometer mixer receivers.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1051-8223	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1427
Permanent link to this record



	Author	Dauler, E. A.; Robinson, B. S.; Kerman, A. J.; Yang, J. K. W.; Rosfjord, E. K. M.; Anant, V.; Voronov, B.; Gol'tsman, G.; Berggren, K. K.
	Title	Multi-element superconducting nanowire single-photon detector			Type	Journal Article
	Year	2007	Publication	IEEE Trans. Appl. Supercond.	Abbreviated Journal	IEEE Trans. Appl. Supercond.
	Volume	17	Issue	2	Pages	279-284
	Keywords	SSPD, SNSPD
	Abstract	A multi-element superconducting nanowire single photon detector (MESNSPD) is presented that consists of multiple independently-biased superconducting nanowire single photon detector (SNSPD) elements that form a continuous active area. A two-element SNSPD has been fabricated and tested, showing no measurable crosstalk between the elements, sub-50-ps relative timing jitter, and four times the maximum counting rate of a single SNSPD with the same active area. The MESNSPD can have a larger active area and higher speed than a single-element SNSPD and the input optics can be designed so that the detector provides spatial, spectral or photon number resolution.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1051-8223	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1428
Permanent link to this record



	Author	Jiang, L.; Antipov, S. V.; Voronov, B. M.; Gol'tsman, G. N.; Zhang, W.; Li, N.; Lin, Z. H.; Yao, Q. J.; Miao, W.; Shi, S. C.; Svechnikov, S. I.; Vakhtomin, Y. B.
	Title	Characterization of the performance of a quasi-optical NbN superconducting HEB mixer			Type	Journal Article
	Year	2007	Publication	IEEE Trans. Appl. Supercond.	Abbreviated Journal	IEEE Trans. Appl. Supercond.
	Volume	17	Issue	2	Pages	395-398
	Keywords	NbN HEB mixers, noise temperature
	Abstract	In this paper we focus mainly on the investigation of the performance of a quasi-optical (planar log-spiral antenna) phonon-cooled NbN superconducting hot electron bolometer (HEB) mixer, which is cryogenically cooled by a close-cycled 4-K cryocooler, at 500 and 850 GHz frequency bands. The mixer's noise performance, stability of IF output power, and local oscillator (LO) power requirement are characterized for three NbN superconducting HEB devices of different sizes. The transmission characteristics of Mylar and Zitex films with incidence waves of an elliptical polarization are also examined by measuring the mixer's noise temperature. The lowest receiver noise temperatures (with no corrections) of 750 and 1100 K are measured at 500 and 850 GHz, respectively. Experimental results also demonstrate that the bigger the HEB device is, the higher the stability of IF output power becomes.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1051-8223	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1429
Permanent link to this record



	Author	Zhang, Wen; Li, Ning; Jiang, Ling; Miao, Wei; Lin, Zhen-Hui; Yao, Qi-Jun; Shi, Sheng-Cai; Chen, Jian; Wu, Pei-Heng; Svechnikov, S. I.; Vachtomin, Y. B.; Antipov, S. V.; Voronov, B. M.; Gol'tsman, G. N.
	Title	Noise behaviour of a THz superconducting hot-electron bolometer mixer			Type	Journal Article
	Year	2007	Publication	Chinese Phys. Lett.	Abbreviated Journal	Chinese Phys. Lett.
	Volume	24	Issue	6	Pages	1778-1781
	Keywords	NbN HEB mixers
	Abstract	A quasi-optical superconducting NbN hot-electron bolometer (HEB) mixer is measured in the frequency range of 0.5–2.5 THz for understanding of the frequency dependence of noise temperature of THz coherent detectors. It has been found that noise temperature increasing with frequency is mainly due to the coupling loss between the quasi-optical planar antenna and the superconducting HEB bridge when taking account of non-uniform distribution of high-frequency current. With the coupling loss corrected, the superconducting HEB mixer demonstrates a noise temperature nearly independent of frequency.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0256-307X	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1430
Permanent link to this record



	Author	Slysz, W.; Wegrzecki, M.; Bar, J.; Grabiec, P.; Gorska, M.; Rieger, E.; Dorenbos, P.; Zwiller, V.; Milostnaya, I.; Minaeva, O.; Antipov, A.; Okunev, O.; Korneev, A.; Smirnov, K.; Voronov, B.; Kaurova, N.; Gol’tsman, G.N.; Kitaygorsky, J.; Pan, D.; Pearlman, A.; Cross, A.; Komissarov, I.; Sobolewski, R.
	Title	Fiber-coupled NbN superconducting single-photon detectors for quantum correlation measurements			Type	Conference Article
	Year	2007	Publication	Proc. SPIE	Abbreviated Journal	Proc. SPIE
	Volume	6583	Issue		Pages	65830J (1 to 11)
	Keywords	NbN SSPD, SNSPD, superconducting single-photon detectors, single-photon detectors, fiber-coupled optical detectors, quantum correlations, superconducting devices
	Abstract	We have fabricated fiber-coupled superconducting single-photon detectors (SSPDs), designed for quantum-correlationtype experiments. The SSPDs are nanostructured ( 100-nm wide and 4-nm thick) NbN superconducting meandering stripes, operated in the 2 to 4.2 K temperature range, and known for ultrafast and efficient detection of visible to nearinfrared photons with almost negligible dark counts. Our latest devices are pigtailed structures with coupling between the SSPD structure and a single-mode optical fiber achieved using a micromechanical photoresist ring placed directly over the meander. The above arrangement withstands repetitive thermal cycling between liquid helium and room temperature, and we can reach the coupling efficiency of up to 33%. The system quantum efficiency, measured as the ratio of the photons counted by SSPD to the total number of photons coupled into the fiber, in our early devices was found to be around 0.3 % and 1% for 1.55 &mgr;m and 0.9 &mgr;m photon wavelengths, respectively. The photon counting rate exceeded 250 MHz. The receiver with two SSPDs, each individually biased, was placed inside a transport, 60-liter liquid helium Dewar, assuring uninterrupted operation for over 2 months. Since the receiver’s optical and electrical connections are at room temperature, the set-up is suitable for any applications, where single-photon counting capability and fast count rates are desired. In our case, it was implemented for photon correlation experiments. The receiver response time, measured as a second-order photon cross-correlation function, was found to be below 400 ps, with timing jitter of less than 40 ps.
	Address
	Corporate Author				Thesis
	Publisher	Spie	Place of Publication		Editor	Dusek, M.; Hillery, M.S.; Schleich, W.P.; Prochazka, I.; Migdall, A.L.; Pauchard, A.
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference	Photon Counting Applications, Quantum Optics, and Quantum Cryptography
	Notes				Approved	no
	Call Number				Serial	1431
Permanent link to this record



	Author	Zinoni, C.; Alloing, B.; Li, L. H.; Marsili, F.; Fiore, A.; Lunghi, L.; Gerardino, A.; Vakhtomin, Y. B.; Smirnov, K. V.; Gol’tsman, G. N.
	Title	Single-photonics at telecom wavelengths using nanowire superconducting single photon detectors			Type	Conference Article
	Year	2007	Publication	CLEO/QELS	Abbreviated Journal	CLEO/QELS
	Volume		Issue		Pages	QTuF6 (1 to 2)
	Keywords	SSPD, SNSPD
	Abstract	Novel single-photon detectors based on NbN superconducting nanostructures promise orders-of- magnitude improvement over InGaAs APDs. We demonstrate this improved performance for the first time by measuring the g(2)(τ) on single photon states produced by a quantum dot at telecom wavelength.
	Address
	Corporate Author				Thesis
	Publisher	Optical Society of America	Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference	Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference and Photonic Applications Systems Technologies
	Notes				Approved	no
	Call Number	Zinoni:07			Serial	1432
Permanent link to this record



	Author	Kerman, A. J.; Dauler, E. A.; Yang, J. K. W.; Rosfjord, K. M.; Anant, V.; Berggren, K. K.; Gol’tsman, G. N.; Voronov, B. M.
	Title	Constriction-limited detection efficiency of superconducting nanowire single-photon detectors			Type	Journal Article
	Year	2007	Publication	Appl. Phys. Lett.	Abbreviated Journal	Appl. Phys. Lett.
	Volume	90	Issue	10	Pages	101110 (1 to 3)
	Keywords	SSPD, SNSPD
	Abstract	We investigate the source of the large variations in the observed detection efficiencies of superconducting nanowire single-photon detectors between many nominally identical devices. Through both electrical and optical measurements, we infer that these variations arise from “constrictions:” highly localized regions of the nanowires where the effective cross-sectional area for superconducting current is reduced. These constrictions limit the bias-current density to well below its critical value over the remainder of the wire, and thus prevent the detection efficiency from reaching the high values that occur in these devices when they are biased near the critical current density. This work is sponsored by the United States Air Force under Contract No. FA8721-05-C-0002.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0003-6951	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1433
Permanent link to this record



	Author	Słysz, W.; Wegrzecki, M.; Bar, J.; Grabiec, P.; Górska, M.; Zwiller, V.; Latta, C.; Böhi, P.; Pearlman, A.J.; Cross, A.S.; Pan, D.; Kitaygorsky, J.; Komissarov, I.; Verevkin, A.; Milostnaya, I.; Korneev, A.; Minayeva, O.; Chulkova, G.; Smirnov, K.; Voronov, B.; Gol’tsman, G.N.; Sobolewski, R.
	Title	Fibre-coupled, single photon detector based on NbN superconducting nanostructures for quantum communications			Type	Journal Article
	Year	2007	Publication	J. Modern Opt.	Abbreviated Journal	J. Modern Opt.
	Volume	54	Issue	2-3	Pages	315-326
	Keywords	NbN SSPD, SNSPD
	Abstract	We present a novel, two-channel, single photon receiver based on two fibre-coupled, NbN, superconducting, single photon detectors (SSPDs). The SSPDs are nanostructured superconducting meanders and are known for ultrafast and efficient detection of visible-to-infrared photons. Coupling between the NbN detector and optical fibre was achieved using a micromechanical photoresist ring placed directly over the SSPD, holding the fibre in place. With this arrangement, we obtained coupling efficiencies up to ∼30%. Our experimental results showed that the best receiver had a near-infrared system quantum efficiency of 0.33% at 4.2 K. The quantum efficiency increased exponentially with the photon energy increase, reaching a few percent level for visible-light photons. The photoresponse pulses of our devices were limited by the meander high kinetic inductance and had the rise and fall times of approximately 250 ps and 5 ns, respectively. The receiver's timing jitter was in the 37 to 58 ps range, approximately 2 to 3 times larger than in our older free-space-coupled SSPDs. We stipulate that this timing jitter is in part due to optical fibre properties. Besides quantum communications, the two-detector arrangement should also find applications in quantum correlation experiments.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0950-0340	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1434
Permanent link to this record



	Author	Jiang, Ling; Miao, Wei; Zhang, Wen; Li, Ning; Lin, Zhen Hui; Yao, Qi Jun; Shi, Sheng-Cai; Svechnikov, Sergey I.; Vakhtomin, Yury B.; Antipov, Sergey V.; Voronov, Boris M.; Kaurova, Natalia S.; Gol'tsman, Gregory N.
	Title	Characterization of quasi-optical NbN phonon-cooled superconducting HEB mixers			Type	Conference Article
	Year	2006	Publication	Proc. 17^th Int. Symp. Space Terahertz Technol.	Abbreviated Journal	Proc. 17^th Int. Symp. Space Terahertz Technol.
	Volume		Issue		Pages	55-58
	Keywords	NbN HEB mixers
	Abstract	In this paper, we thoroughly investigate the performance of quasi-optical NbN phonon-cooled superconducting hot-electron bolometer (HEB) mixers, cryogenically cooled by a close-cycled 4-K refrigerator at 500 GI-1z and 850 GHz. The uncorrected lowest receiver noise Abstract---In temperatures measured are 800 K at 500 CHz without anti-reflection coating, and 1000 K @ 850 GHz with a 50 11M thick Mylar anti-reflection coating. The dependence of receiver noise temperature on the critical current and bath temperature of HEB mixer is also investigated here. Lifetime of quasi-optical superconducting NbN HEB mixers of different volumes, room temperature resistances, and critical temperatures are thoroughly studied. Increased room temperature resistance with time over the initial resistance changes between 1 and 1.2, and the reduced critical current with time over the initial value fluctuates slightly around 0.7 for most HEB mixers even of different volumes, room temperature resistances, and critical temperatures. The critical current degrades sharply vvhile room temperature resistance varies over 1.25.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1435
Permanent link to this record



	Author	Gao, J.R.; Hiajenius, M.; Yang, Z.Q.; Klapwijk, T.M.; Miao, W.; Shi, S. C.; Voronov, B.; Gortsman, G.
	Title	Direct comparison of the sensitivity of a spiral and a twin-slot antenna coupled HEB mixer at 1.6 THz			Type	Conference Article
	Year	2006	Publication	Proc. 17^th Int. Symp. Space Terahertz Technol.	Abbreviated Journal	Proc. 17^th Int. Symp. Space Terahertz Technol.
	Volume		Issue		Pages	59-62
	Keywords	NbN HEB mixers
	Abstract	To make a direct comparison of the sensitivity between a spiral and a twin slot antenna coupled HEB mixer, we designed both types of mixers and fabricated them in a single processing run and on the same wafer. Both mixers have similar dimensions of NbN bridges (1.5-2 pm x0.2 pm). At 1.6 THz we obtained a nearly identical receiver noise temperature from both mixers (only 5% difference), which is in a good agreement with the simulation based on semi analytical models for both antennas. In addition, by using a bandpass filter to reduce the direct detection effect and lowering the bath temperature to 2.4 K, we measured the lowest receiver noise temperature of 700 K at 1.63 THz using the twin-slot antenna mixer.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1436
Permanent link to this record



	Author	Baselmans, J. J. A.; Baryshev, A.; Hajenius, M.; Gao, J. R.; Klapwijk, T. M.; Voronov, B.; Gol'tsman, G.
	Title	Influence of the direct response on the heterodyne sensitivity of hot electron bolometer mixers			Type	Abstract
	Year	2006	Publication	Proc. 17^th Int. Symp. Space Terahertz Technol.	Abbreviated Journal	Proc. 17^th Int. Symp. Space Terahertz Technol.
	Volume		Issue		Pages	81
	Keywords	NbN HEB mixers
	Abstract	We present a detailed experimental study of the direct detection effect in a small volume (0.15pm x lpm) NbN hot electron bolometer mixer. It is a quasioptical mixer with a twin slot antenna designed for 700 GHz and the measurement was done at a LO frequency of 670 GHz. The direct detection effect is characterized by a change in the mixer bias current when switching broadband radiation from a 300 K hot load to a 77 K cold load in a standard Y factor measurement. The result is, depending on the receiver under study, an increase or decrease in the receiver noise temperature. We find that the small signal noise temperature, which is the noise temperature that would be observed without the presence of the direct detection effect, and thus the one that is relevant for an astronomical observation, is 20% lower than the noise temperature obtained using 300 K and 77 K calibration loads. Thus, in our case the direct detection effect reduces the mixer sensitivity. These results are in good agreement with previous measurement at THz frequencies [1]. Other experiments report an increase in mixer sensitivity [2]. To analyze this discrepancy we have designed a separate set of experiments to find out the physical origin of the direct detection effect. Possible candidates are the bias current dependence of the mixer gain and the bias current dependence of the IF match. We measured directly the change in mixer IF match and receiver gain due to the direct detection effect. From these measurements we conclude that the direct detection effect is caused by a combination of bias current reduction when switching form the 77 K to the 300 K load in combination with the bias current dependence of the receiver gain. The bias current dependence of the receiver gain is shown to be mainly caused by the current dependence of the mixer gain. We also find that an increase in receiver sensitivity due to the direct detection effect is only possible if the noise temperature change due to the direct detection is dominated by the mixer-amplifier IF match. [1] J.J.A. Baselmans, A. Baryshev, S.F. Reker, M. Hajenius, J.R. Gao, T.M. Klapwijk, Yu.Vachtomin, S. Maslennikov, S. Antipov, B. Voronov, and G. Gol'tsman., Appl. Phys. Lett. 86, 163503 (2005). [2] S. Svechnokov, A. Verevkin, B. Voronov, E. Menschikov. E. Gershenzon, G. Gol'tsman, 9th Int. Symp. On Space THz. Techn., 45, (1999).
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1437
Permanent link to this record



	Author	Tarkhov, M.; Morozov, D.; Mauskopf, P.; Seleznev, V.; Korneev, A.; Kaurova, N.; Rubtsova, I.; Minaeva, O.; Voronov, B.; Goltsman, G.
	Title	Single photon counting detector for THz radioastronomy			Type	Conference Article
	Year	2006	Publication	Proc. 17^th Int. Symp. Space Terahertz Technol.	Abbreviated Journal	Proc. 17^th Int. Symp. Space Terahertz Technol.
	Volume		Issue		Pages	119-122
	Keywords	NbN SSPD, SNSPD
	Abstract	In this paper we present the results of the research on the superconducting NbN-ultrathin-film single- photon detectors (SSPD) which are capable to detect single quanta in middle IR range. The detection mechanism is based on the hotspot formation in quasi-two-dimensional superconducting structures upon photon absorption. Spectral measurements showed that up to 5.7 gm wavelength (52 THz) the SSPD exhibits single-photon sensitivity. Reduction of operation temperature to 1.6 K allowed us to measure quantum efficiency of -4% at 60 THz. Although further decrease of the operation temperature far below 1 K does not lead to any significant increase of quantum efficiency. We expect that the improvement of the SSPD's performance at reduced operation temperature will make SSPD a practical detector with high characteristics for much lower THz frequencies as well.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1438
Permanent link to this record



	Author	Gao, J. R.; Hajenius, M.; Tichelaar, F. D.; Voronov, B.; Grishina, E.; Klapwijk, T. M.; Gol'tsman, G.; Zorman, C. A.
	Title	Can NbN films on 3C-SiC/Si change the IF bandwidth of hot electron bolometer mixers?			Type	Conference Article
	Year	2006	Publication	Proc. 17^th Int. Symp. Space Terahertz Technol.	Abbreviated Journal	Proc. 17^th Int. Symp. Space Terahertz Technol.
	Volume		Issue		Pages	187-189
	Keywords	NbN HEB mixers
	Abstract	We realized ultra thin NbN films sputtered grown on a 3C-SiC/Si substrate. The film with a thickness of 3.5-4.5 nm shows a 1', of 11.8 K, which is the highest I`, observed among ultra thin NbN films on different substrates. The high-resolution transmission electron microscopy (HRTEM) studies show that the film has a monocrystalline structure, confirming the epitaxial growth on the 3C-SiC. Based on a two-temperature model and input parameters from standard NbN films on Si, simulations predict that the new film can increase the IF bandwidth of a HEB mixer by about a factor of 2 in comparison to the standard films. In addition, we find standard NbN films on Si with a T c of 9.4 K have a thickness of around 5.5 nm, being thicker than expected (3.5 nm).
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1439
Permanent link to this record



	Author	Gol'tsman, G.; Maslennikov, S.; Finkel, M.; Antipov, S.; Kaurova, N.; Grishina, E.; Polyakov, S.; Vachtomin, Y.; Svechnikov, S.; Smirnov, K.; Voronov, B.
	Title	Nanostructured ultrathin NbN film as a terahertz hot-electron bolometer mixer			Type	Conference Article
	Year	2006	Publication	Proc. MRS	Abbreviated Journal	Proc. MRS
	Volume	935	Issue		Pages	210 (1 to 6)
	Keywords	NbN HEB mixers
	Abstract	Planar spiral antenna coupled and directly lens coupled NbN HEB mixer structures are studied. An additional MgO buffer layer between the superconducting film and Si substrate is introduced. The buffer layer enables us to increase the gain bandwidth of a HEB mixer due to better acoustic transparency. The gain bandwidth is widened as NbN film thickness decreases and amounts to 5.2 GHz. The noise temperature of antenna coupled mixer is 1300 and 3100 K at 2.5 and 3.8 THz respectively. The structure and composition of NbN films is investigated by X-ray diffraction spectroscopy methods. Noise performance degradation at LO frequencies more than 3 THz is due to the use of a planar antenna and signal loss in contacts between the antenna and the sensitive NbN bridge. The mixer is reconfigured for operation at higher frequencies in a manner that receiver’s noise temperature is only 2300 K (3 times of quantum limit) at LO frequency of 30 THz.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0272-9172	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	1440
Permanent link to this record



	Author	Ryabchun, S.; Tong, C.-yu E.; Blundell, R.; Kimberk, R.; Gol’tsman, G.
	Title	Effect of microwave radiation on the stability of terahertz hot-electron bolometer mixers			Type	Conference Article
	Year	2006	Publication	Proc. SPIE	Abbreviated Journal	Proc. SPIE
	Volume	6373	Issue		Pages	63730J (1 to 5)
	Keywords	NbN HEB mixers, hot-electron bolometer mixers, stability, Allan variance, LO power fluctuations
	Abstract	We report our studies of the effect of microwave radiation, with a frequency much lower than that corresponding to the energy gap of the superconductor, on the performance of the NbN hot-electron bolometer (HEB) mixer incorporated into a THz heterodyne receiver. It is shown that exposing the HEB mixer to microwave radiation does not result in a significant rise of the receiver noise temperature and degradation of the mixer conversion gain so long as the level of microwave power is small compared to the local oscillator drive. Hence the injection of a small, but controlled amount of microwave radiation enables active compensation of local oscillator power and coupling fluctuations which can significantly degrade the stability of HEB mixer receivers.
	Address
	Corporate Author				Thesis
	Publisher	SPIE	Place of Publication		Editor	Anwar, M.; DeMaria, A.J.; Shur, M.S.
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference	Terahertz Physics, Devices, and Systems
	Notes				Approved	no
	Call Number				Serial	1441
Permanent link to this record