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Author Marsili, F.; Bitauld, D.; Fiore, A.; Gaggero, A.; Leoni, R.; Mattioli, F.; Divochiy, A.; Korneev, A.; Seleznev, V.; Kaurova, N.; Minaeva, O.; Goltsman, G.
Title Superconducting parallel nanowire detector with photon number resolving functionality Type Journal Article
Year 2009 Publication J. Modern Opt. Abbreviated Journal J. Modern Opt.
Volume 56 Issue 2-3 Pages 334-344
Keywords (up) PNR; SSPD; SNSPD; thin superconducting films; photon number resolving detector; multiplication noise; telecom wavelength; NbN
Abstract We present a new photon number resolving detector (PNR), the Parallel Nanowire Detector (PND), which uses spatial multiplexing on a subwavelength scale to provide a single electrical output proportional to the photon number. The basic structure of the PND is the parallel connection of several NbN superconducting nanowires (100 nm-wide, few nm-thick), folded in a meander pattern. Electrical and optical equivalents of the device were developed in order to gain insight on its working principle. PNDs were fabricated on 3-4 nm thick NbN films grown on sapphire (substrate temperature TS=900C) or MgO (TS=400C) substrates by reactive magnetron sputtering in an Ar/N2 gas mixture. The device performance was characterized in terms of speed and sensitivity. The photoresponse shows a full width at half maximum (FWHM) as low as 660ps. PNDs showed counting performance at 80 MHz repetition rate. Building the histograms of the photoresponse peak, no multiplication noise buildup is observable and a one photon quantum efficiency can be estimated to be QE=3% (at 700 nm wavelength and 4.2 K temperature). The PND significantly outperforms existing PNR detectors in terms of simplicity, sensitivity, speed, and multiplication noise.
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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 RPLAB @ gujma @ Serial 701
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Author Rabanus, D.; Graf, U. U.; Philipp, M.; Ricken, O.; Stutzki, J.; Vowinkel, B.; Wiedner, M. C.; Walther, C.; Fischer, M.; Faist, J.
Title Phase locking of a 1.5 terahertz quantum cascade laser and use as a local oscillator in a heterodyne HEB receiver Type Journal Article
Year 2009 Publication Optics Express Abbreviated Journal
Volume 17 Issue 3 Pages 1159-1168
Keywords (up) QCL heterodyne, 300 uW at 1.5 THz, HEB mixer
Abstract We demonstrate for the first time the closure of an electronic phase lock loop for a continuous–wave quantum cascade laser (QCL) at 1.5 THz. The QCL is operated in a closed cycle cryo cooler. We achieved a frequency stability of better than 100 Hz, limited by the resolution bandwidth of the spectrum analyser. The PLL electronics make use of the intermediate frequency (IF) obtained from a hot electron bolometer (HEB) which is downconverted to a PLL IF of 125 MHz. The coarse selection of the longitudinal mode and the fine tuning is achieved via the bias voltage of the QCL. Within a QCL cavity mode, the free-running QCL shows frequency fluctuations of about 5 MHz, which the PLL circuit is able to control via the Stark–shift of the QCL gain material. Temperature dependent tuning is shown to be nonlinear, and of the order of -16 MHz/K. Additionally we have used the QCL as local oscillator (LO) to pump an HEB and perform, again for the first time at 1.5 THz, a heterodyne experiment, and obtain a receiver noise temperature of 1741 K.
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Notes Approved no
Call Number Serial 628
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Author Sekine, Norihiko; Hosako, Iwao
Title Intensity modulation of terahertz quantum cascade lasers under external light injection Type Journal Article
Year 2009 Publication Applied Physics Letters Abbreviated Journal Appl. Phys. Lett.
Volume 95 Issue Pages 201106(1-3)
Keywords (up) QCL modulation, THz, terahertz
Abstract We investigated the light-current characteristics of terahertz (THz) quantum cascade lasers under external light injection, which excites interband transitions in the active materials. It was found that the amount of reduction in the THz power was constant for all injection currents above threshold, and the dependence of the reduction amount on the wavelength of the external light was observed to show a resonancelike feature. The dominant intensity modulation mechanism was found to be the loss change caused by interband transitions in the active region. Further, the effective coupling efficiency plays an important role in the intensity modulation.
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Notes Approved no
Call Number Serial 630
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Author Stucki, Damien; Barreiro, Claudio; Fasel, Sylvain; Gautier, Jean-Daniel; Gay, Olivier; Gisin, Nicolas; Thew, Rob; Thoma, Yann; Trinkler, Patrick; Vannel, Fabien; Zbinden, Hugo
Title Continuous high speed coherent one-way quantum key distribution Type Journal Article
Year 2009 Publication Optics Express Abbreviated Journal Opt. Express
Volume 17 Issue 16 Pages 13326-13334
Keywords (up) quantum cryptography, QKD, PNS, SSPD, coherent one way, COW
Abstract Quantum key distribution (QKD) is the first commercial quantum technology operating at the level of single quanta and is a leading light for quantum-enabled photonic technologies. However, controlling these quantum optical systems in real world environments presents significant challenges. For the first time, we have brought together three key concepts for future QKD systems: a simple high-speed protocol; high performance detection; and integration both, at the component level and for standard fibre network connectivity. The QKD system is capable of continuous and autonomous operation, generating secret keys in real time. Laboratory and field tests were performed and comparisons made with robust InGaAs avalanche photodiodes and superconducting detectors. We report the first real world implementation of a fully functional QKD system over a 43dB-loss (150km) transmission line in the Swisscom fibre optic network where we obtained average real-time distribution rates over 3 hours of 2.5bps.
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Notes Approved no
Call Number RPLAB @ akorneev @ Serial 602
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Author Esteban, Eduin; Serna, Hernandez
Title Quantum key distribution protocol with private-public key Type Journal Article
Year 2009 Publication arXiv Abbreviated Journal arXiv
Volume Issue Pages 3
Keywords (up) quantum cryptography; QKD; protocol
Abstract A quantum cryptographic protocol based in public key cryptography combinations and private key cryptography is presented. Unlike the BB84 protocol 1 and its many variants 2,3 two quantum channels are used. The present research does not make reconciliation mechanisms of information to derive the key. A three related system of key distribution are described.
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Notes arXiv: 0908.2146 Approved no
Call Number RPLAB @ gujma @ Serial 756
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Author Treuttel, J.; Thomas, B.; Maestrini, A.; Wang, H.; Alderman, B.; Siles, J.V.; Davis, S.; Narhi, T.
Title A 380 GHz sub-harmonic mixer using MMIC foundry based Schottky diodes transferred onto quartz substrate Type Conference Article
Year 2009 Publication Proc. 20th Int. Symp. Space Terahertz Technol. Abbreviated Journal
Volume Issue Pages
Keywords (up) Schottky
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Charlottesville, Virginia, USA Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
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Notes Approved no
Call Number Serial 586
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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 (up) 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.
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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
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Author Karpov, A.; Miller, D.; Stern, J. A.; Bumble, B.; LeDuc, H. G.; Zmuidzinas, J.
Title Broadband SIS mixer for 1 THz Band Type Conference Article
Year 2009 Publication Proc. 20th Int. Symp. Space Terahertz Technol. Abbreviated Journal
Volume Issue Pages 35-35
Keywords (up) SIS mixer, noise temperature
Abstract We report the development of a low noise and broadband SIS mixer aimed for 1 THz channel of the Caltech Airborne Submillimeter Interstellar Medium Investigations Receiver (CASIMIR), designed for the Stratospheric Observatory for Far Infrared Astronomy, (SOFIA). The mixer uses an array of 0.24 µm² Nb/Al-AlN/NbTiN SIS junctions with critical current density of 30-50 KA/cm². The junctions are shaped in order to optimize the suppression of the Josephson DC currents. We are using a double slot planar antenna to couple the mixer chip with the telescope beam. The RF matching microcircuit is made using Nb and gold films. The mixer IF circuit is designed to cover 4 – 8 GHz band. A test receiver with the new mixer has a low noise operation in a 0.87 – 1.12 THz band. The minimum DSB receiver noise measured at 1 THz is 260 K (Y=1.64), apparently the lowest reported up to date. The receiver noise corrected for the loss in the LO injection beam splitter and in the cryostat window is 200 K. The combination of a broad operation band of about 250 GHz with a low receiver noise is making the new mixer a useful element for application at SOFIA. We will discuss the prospective of a further improvement of the sensitivity and extension of the upper frequency of operation of SIS mixer.
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Notes Approved no
Call Number Serial 614
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Author Uzawa, Y.; Kojima, T.; Kroug, M.; Takeda, M.; Candotti, M.; Fujii, Y.; Shan, W.-L.; Kaneko, K.; Shitov, S.; Wang, M.-J.
Title Development of the 787-950 GHz ALMA band 10 cartridge Type Conference Article
Year 2009 Publication Proc. 20th Int. Symp. Space Terahertz Technol. Abbreviated Journal
Volume Issue Pages 12-12
Keywords (up) SIS mixer, noise temperature, ALMA, band 10
Abstract We are developing the Atacama Large Millimeter/Submillimeter Array (ALMA) Band 10 (787-950 GHz) receiver cartridge. The incoming beam from the 12-m antenna is reflected by a pair of two ellipsoidal mirrors placed in the cartridge, and then split into two orthogonal polarizations by a free-standing wire-grid. Each beam enters a corrugated feed horn attached to a double-side-band (DSB) mixer block. The mixer uses a full-height waveguide and an NbTiN- or NbN-based superconductor-insulator-superconductor (SIS) mixer chip. We are testing the following three types of mixer chips: 1) Nb SIS junctions + NbTiN/SiO2/Al tuning circuits on a quartz substrate, 2) Nb SIS junctions + NbN/SiO2/Al tuning circuits on an MgO substrate, and 3) NbN SIS junctions + NbN or NbTiN tuning circuits on an MgO substrate. The IF system uses a 4-12-GHz cooled low-noise InP-based MMIC amplifier developed by Caltech. So far, the type 1) has shown the best performance. At LO frequencies from 800 to 940 GHz, the mixer noise temperatures measured by using the standard Y-factor method were below 240 K at an operating physical temperature of 4 K. The lowest noise temperature, 169 K, was obtained at the center frequency of the band 10, as designed. These well-developed technologies will be implemented in the band 10 cartridge to achieve the ALMA specifications.
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Notes Approved no
Call Number Serial 615
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Author Billade, Bhushan; Belitsky, Victor; Pavolotsky, Alexey; Lapkin, Igor; Kooi, Jacob
Title ALMA band 5 (163-211 GHz) sideband separation mixer Type Conference Article
Year 2009 Publication Proc. 20th Int. Symp. Space Terahertz Technol. Abbreviated Journal
Volume Issue Pages 19-23
Keywords (up) SIS mixer, noise temperature, ALMA, band 5
Abstract We present the design of ALMA Band 5 sideband separation SIS mixer and experimental results for the double side band mixer and first measurement results 2SB mixer. In this mixer, the LO injection circuitry is integrated on the mixer substrate using a directional coupler, combining microstrip lines with slot-line branches in the ground plane. The isolated port of the LO coupler is terminated by wideband floating elliptical termination. The mixer employs two SIS junctions with junction area of 3 µm² each, in the twin junction configuration, followed by a quarter wave transformer to match the RF probe. 2SB mixer uses two identical but mirrored chips, whereas each DSB mixer has the same end-piece configuration. The 2S mixer has modular design such that DSB mixers are measured independently and then integrated into 2SB simply by placing around the middle piece. Measurements of the DSB mixer show noise temperature of around 40K over the entire band. 2SB mixer is not fully characterized yet, however, preliminary measurement indicates SSB (un-corrected) noise temperature of 80K.
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Notes Approved no
Call Number Serial 616
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