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Author Beck, Matthias; Leiderer, Paul; Kabanov, Viktor V.; Gol'tsman, Gregory; Helm, Manfred; Demsar, Jure
Title (up) 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.
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Notes Approved no
Call Number Serial 1383
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Author Beck, M.; Klammer, M.; Lang, S.; Leiderer, P.; Kabanov, V. V.; Gol’tsman, G. N.; Demsar, J.
Title (up) 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.
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Notes Duplicated as 641 Approved no
Call Number Serial 1388
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Author Gershenzon, E.; Goltsman, G.; Elantev, A.; Kagane, M.
Title (up) Energy-spectrum of small donors and acceptors in germanium and effect of magnetic-field on it Type Conference Article
Year 1978 Publication Izv. Akad. Nauk SSSR, Seriya Fizicheskaya Abbreviated Journal Izv. Akad. Nauk SSSR, Seriya Fizicheskaya
Volume 42 Issue 6 Pages 1142-1148
Keywords energy spectrum, Ge, magnetic field
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Notes Approved no
Call Number Serial 1722
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Author Simonov, N. O.; Korneeva, Y. P.; Korneev, A. A.; Goltsman, G. N.
Title (up) Enhance of the superconducting properties of the NbN/Au bilayer bridges Type Conference Article
Year 2020 Publication J. Phys.: Conf. Ser. Abbreviated Journal J. Phys.: Conf. Ser.
Volume 1695 Issue Pages 012132 (1 to 4)
Keywords SSPD, SNSPD
Abstract We experimentally demonstrate strong temperature dependence of the critical current of the superconducting 600-nm-wide and 5-μm-long bridge made of NbN/Au bilayer. The result is achieved due to the proximity effect realized between the highly disordered superconducting NbN layer and low resistive normal-metal Au layer.
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Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1742-6588 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1263
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Author Shcheslavskiy, V.; Morozov, P.; Divochiy, A.; Vakhtomin, Y.; Smirnov, K.; Becker, W.
Title (up) Erratum: “Ultrafast time measurements by time-correlated single photon counting coupled with superconducting single photon detector” [Rev. Sci. Instrum. 87, 053117 (2016)] Type Miscellaneous
Year 2016 Publication Rev. Sci. Instrum. Abbreviated Journal Rev. Sci. Instrum.
Volume 87 Issue 6 Pages 069901
Keywords SSPD, SNSPD, TCSPC, jitter
Abstract In the original paper1the Ref. 10 should be M. Sanzaro, N. Calandri, A. Ruggeri, C. Scarcella, G. Boso, M. Buttafava, and A. Tosi, Proc. SPIE9370, 93701T (2015).
Address Becker & Hickl GmbH, Nahmitzer Damm 30, Berlin 12277, 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 0034-6748 ISBN Medium
Area Expedition Conference
Notes PMID:27370512 Approved no
Call Number Serial 1810
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Author Karasik, B. S.; Zorin, M. A.; Milostnaya, I. I.; Elantev, A. I.; Gol’tsman, G. N.; Gershenzon, E. M.
Title (up) Evidence of subnanosecond transition stage in S-N current switching of YBaCuO films Type Conference Article
Year 1994 Publication Proc. SPIE Abbreviated Journal Proc. SPIE
Volume 2160 Issue Pages 74-82
Keywords YBCO HTS switches
Abstract We report on a study of S-N and N-S current switching in high quality YBaCuO films deposited onto ZrO2 and NdGaO3 substrates. The films 60-120 nm thick prepared by laser ablation were structured into single strips and were provided with gold contacts. We monitored the time dependence of the resistance upon application of the voltage step on the film. Experiment performed within certain ranges of voltage amplitudes and temperatures showed the occurrence of the fast stage both in S-N (shorter than 300 ps) and N-S transition. We discuss the mechanism of switching taking into account the hot electron phenomena in YBaCuO. The contributions of various thermal processes in the subsequent stage of the resistance dynamic are also discussed. The basic limiting characteristics (average dissipated power, minimum work done for switching, maximum repetition rate) of a picosecond switch which is proposed to be developed are estimated.
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Publisher SPIE Place of Publication Editor Buhrman, R.A.; Clarke, J.T.; Daly, K.; Koch, R.H.; Luine, J.A.; Simon, R.W.
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference Superconductive Devices and Circuits
Notes Approved no
Call Number Serial 1638
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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 (up) 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.
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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
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Author An, P.; Kovalyuk, V.; Golikov, A.; Zubkova, E.; Ferrari, S.; Korneev, A.; Pernice, W.; Goltsman, G.
Title (up) Experimental optimisation of O-ring resonator Q-factor for on-chip spontaneous four wave mixing Type Conference Article
Year 2018 Publication J. Phys.: Conf. Ser. Abbreviated Journal J. Phys.: Conf. Ser.
Volume 1124 Issue Pages 051047
Keywords planar O-ring resonators, Q-factor
Abstract In this paper we experimentally studied the influence of geometrical parameters of the planar O-ring resonators on its Q-factor and losses. We systematically changed the gap between the bus waveguide and the ring, as well as the width of the ring. We found the highest Q = 5×105 for gap 2.0 μm and the ring width 2 μm. This work is important for further on-chip SFWM applications since the generation rate of the biphoton field strongly depends on the quality factor as Q3
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Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1742-6588 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1191
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Author Polyakova, M. I.; Florya, I. N.; Semenov, A. V.; Korneev, A. A.; Goltsman, G. N.
Title (up) Extracting hot-spot correlation length from SNSPD tomography data Type Conference Article
Year 2019 Publication J. Phys.: Conf. Ser. Abbreviated Journal J. Phys.: Conf. Ser.
Volume 1410 Issue Pages 012166 (1 to 4)
Keywords SSPD, SNSPD, quantum detector tomography, QDT
Abstract We present data of quantum detector tomography for the samples specifically optimized for this problem. Using this method, we take results of hot-spot correlation length of 17 ± 2 nm.
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Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1742-6588 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1273
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Author Ryabchun, S. A.; Tretyakov, I. V.; Finkel, M. I.; Maslennikov, S. N.; Kaurova, N. S.; Seleznev, V. A.; Voronov, B. M.; Goltsman, G. N.
Title (up) Fabrication and characterisation of NbN HEB mixers with in situ gold contacts Type Conference Article
Year 2008 Publication Proc. 19th Int. Symp. Space Terahertz Technol. Abbreviated Journal Proc. 19th Int. Symp. Space Terahertz Technol.
Volume Issue Pages 62-67
Keywords HEB, mixer, NbN, in-situ contacts
Abstract We present our recent results of the fabrication and testing of NbN hot-electron bolometer mixers with in situ gold contacts. An intermediate frequency bandwidth of about 6 GHz has been measured for the mixers made of a 3.5-nm NbN film on a plane Si substrate with in situ gold contacts, compared to 3.5 GHz for devices made of the same film with ex situ gold contacts. The increase in the intermediate frequency bandwidth is attributed to additional diffusion cooling through the improved contacts, which is further supported by the its dependence on the bridge length: intermediate frequency bandwidths of 3.5 GHz and 6 GHz have been measured for devices with lengths of 0.35 μm and 0.16 μm respectively at a local oscillator frequency of 300 GHz near the superconducting transition. At a local oscillator frequency of 2.5 THz the receiver has offered a DSB noise temperature of 950 K. When compared to the previous result of 1300 K obtained at the same local oscillator frequency for devices fabricated with an ex situ route, such a low value of the noise temperature may also be attributed to the improved gold contacts.
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Publisher Place of Publication Groningen, Netherlands Editor
Language Summary Language Original Title
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Notes Approved no
Call Number Serial 412
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