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Author Шангина, Е. Л.; Смирнов, К. В.; Морозов, Д. В.; Ковалюк, В. В.; Гольцман, Г. Н.; Веревкин, А. А.; Торопов, А. И.
Title Концентрационная зависимость полосы преобразования смесителей субмиллиметрового диапазона на основе наноструктур AlGaAs/GaAs Type Journal Article
Year 2010 Publication Изв. РАН Сер. Физ. Abbreviated Journal Изв. РАН Сер. Физ.
Volume 74 Issue 1 Pages 110-112
Keywords 2DEG AlGaAs/GaAs heterostructures, THz heterodyne detectors, IF bandwidth
Abstract Методом субмиллиметровой спектроскопии с высоким временным разрешением при Т = 4.2 К измерена концентрационная зависимость полосы преобразования гетеродинного детектирования гетероструктур AlGaAs/GaAs с двумерным электронным газом. С увеличением концентрации двумерных электронов ns = (1.6–6.6) · 1011см-2 ширина полосы преобразования f3dB уменьшается от 245 до 145 МГц. В исследованной области концентраций наблюдается зависимость f3dB , обусловленная рассеянием электронов на деформационном потенциале акустических фононов и пьезоэлектрическим рассеянием.
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Language Russian Summary Language (up) Original Title
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Notes Duplicated as 1217 Approved no
Call Number RPLAB @ gujma @ Serial 642
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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. 21th Int. Symp. Space Terahertz Technol. Abbreviated Journal Proc. 21th 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
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Call Number Serial 1393
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Author Annunziata, Anthony J.; Quaranta, Orlando; Santavicca, Daniel F.; Casaburi, Alessandro; Frunzio, Luigi; Ejrnaes, Mikkel; Rooks, Michael J.; Cristiano, Roberto; Pagano, Sergio; Frydman, Aviad; Prober, Daniel E.
Title Reset dynamics and latching in niobium superconducting nanowire single-photon detectors Type Journal Article
Year 2010 Publication J. Appl. Phys. Abbreviated Journal
Volume 108 Issue 8 Pages 7
Keywords SNSPD
Abstract We study the reset dynamics of niobium (Nb) superconducting nanowire single-photon detectors (SNSPDs) using experimental measurements and numerical simulations. The numerical simulations of the detection dynamics agree well with experimental measurements, using independently determined parameters in the simulations. We find that if the photon-induced hotspot cools too slowly, the device will latch into a dc resistive state. To avoid latching, the time for the hotspot to cool must be short compared to the inductive time constant that governs the resetting of the current in the device after hotspot formation. From simulations of the energy relaxation process, we find that the hotspot cooling time is determined primarily by the temperature-dependent electron-phonon inelastic time. Latching prevents reset and precludes subsequent photon detection. Fast resetting to the superconducting state is, therefore, essential, and we demonstrate experimentally how this is achieved. We compare our results to studies of reset and latching in niobium nitride SNSPDs.
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Call Number RPLAB @ gujma @ Serial 649
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Author Terai, Hirotaka; Miki, Shigehito; Yamashita, Taro; Makise, Kazumasa; Wang, Zhen
Title Demonstration of single-flux-quantum readout operation for superconducting single-photon detectors Type Journal Article
Year 2010 Publication Applied Physics Letters Abbreviated Journal Appl. Phys. Lett.
Volume 97 Issue 11 Pages 3
Keywords SSPD
Abstract A readout circuit using superconducting single-flux-quantum (SFQ) circuits has been developed to realize an independently addressable array of superconducting single-photon detectors (SSPDs). We tested the SFQ readout circuits by connecting with SSPDs. The error rates of readout circuits were below 10–5 for input signal amplitude of greater than 18.2 μA. Detection efficiencies (DEs) for single-photon incidents were measured both with and without the connection of a readout circuit. The observed DEs traced almost the same curves regardless of the connection of the readout circuit, except that the SSPD is likely to latch by connecting the readout circuit.
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Call Number RPLAB @ gujma @ Serial 654
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Author Tanner, M. G.; Natarajan, C. M.; Pottapenjara, V. K.; O'Connor, J. A.; Warburton, R. J.; Hadfield, R. H.; Baek, B.; Nam, S.; Dorenbos, S. N.; Bermúdez Ureña, E.; Zijlstra, T.; Klapwijk, T. M.; Zwiller, V.
Title Enhanced telecom wavelength single-photon detection with NbTiN superconducting nanowires on oxidized silicon Type Journal Article
Year 2010 Publication Applied Physics Letters Abbreviated Journal Appl. Phys. Lett.
Volume 96 Issue 22 Pages 3
Keywords SNSPD
Abstract Superconducting nanowire single-photon detectors (SNSPDs) have emerged as a highly promising infrared single-photon detector technology. Next-generation devices are being developed with enhanced detection efficiency (DE) at key technological wavelengths via the use of optical cavities. Furthermore, new materials and substrates are being explored for improved fabrication versatility, higher DE, and lower dark counts. We report on the practical performance of packaged NbTiN SNSPDs fabricated on oxidized silicon substrates in the wavelength range from 830 to 1700 nm. We exploit constructive interference from the SiO2/Si interface in order to achieve enhanced front-side fiber-coupled DE of 23.2 % at 1310 nm, at 1 kHz dark count rate, with 60 ps full width half maximum timing jitter.
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Notes Approved no
Call Number RPLAB @ gujma @ Serial 655
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