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Author Sidorova, M.; Semenov, Alexej D.; Hübers, H.-W.; Ilin, K.; Siegel, M.; Charaev, I.; Moshkova, M.; Kaurova, N.; Goltsman, G. N.; Zhang, X.; Schilling, A.
Title Electron energy relaxation in disordered superconducting NbN films Type Journal Article
Year 2020 Publication Phys. Rev. B Abbreviated Journal Phys. Rev. B
Volume 102 Issue 5 Pages (down) 054501 (1 to 15)
Keywords NbN SSPD, SNSPD, HEB, bandwidth, relaxation time
Abstract We report on the inelastic-scattering rate of electrons on phonons and relaxation of electron energy studied by means of magnetoconductance, and photoresponse, respectively, in a series of strongly disordered superconducting NbN films. The studied films with thicknesses in the range from 3 to 33 nm are characterized by different Ioffe-Regel parameters but an almost constant product qTl (qT is the wave vector of thermal phonons and l is the elastic mean free path of electrons). In the temperature range 14–30 K, the electron-phonon scattering rates obey temperature dependencies close to the power law 1/τe−ph∼Tn with the exponents n≈3.2–3.8. We found that in this temperature range τe−ph and n of studied films vary weakly with the thickness and square resistance. At 10 K electron-phonon scattering times are in the range 11.9–17.5 ps. The data extracted from magnetoconductance measurements were used to describe the experimental photoresponse with the two-temperature model. For thick films, the photoresponse is reasonably well described without fitting parameters, however, for thinner films, the fit requires a smaller heat capacity of phonons. We attribute this finding to the reduced density of phonon states in thin films at low temperatures. We also show that the estimated Debye temperature in the studied NbN films is noticeably smaller than in bulk material.
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ISSN 2469-9950 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1266
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Author Zolotov, P.; Divochiy, A.; Vakhtomin, Y.; Moshkova, M.; Morozov, P.; Seleznev, V.; Smirnov, K.
Title Photon-number-resolving SSPDs with system detection efficiency over 50% at telecom range Type Conference Article
Year 2018 Publication Proc. AIP Conf. Abbreviated Journal
Volume 1936 Issue 1 Pages (down) 020019
Keywords NbN PNR SSPD, SNSPD
Abstract We used technology of making high-efficiency superconducting single-photon detectors as a basis for improvement of photon-number-resolving devices. By adding optical cavity and using an improved NbN superconducting film, we enhanced previously reported system detection efficiency at telecom range for such detectors. Our results show that implementation of optical cavity helps to develop four-section device with quantum efficiency over 50% at 1.55 µm. Performed experimental studies of detecting multi-photon optical pulses showed irregularities over defining multi-photon through single-photon quantum efficiency.
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Notes Approved no
Call Number doi:10.1063/1.5025457 Serial 1231
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Author Moshkova, M.; Morozov, P.; Divochiy, A.; Vakhtomin, Y.; Smirnov, K.
Title Large active area superconducting single photon detector Type Conference Article
Year 2019 Publication J. Phys.: Conf. Ser. Abbreviated Journal J. Phys.: Conf. Ser.
Volume 1410 Issue Pages (down) 012139
Keywords SSPD, SNSPD
Abstract We present development of large active area superconducting single-photon detectors well coupled with standard 50 μm-core multi-mode fiber. The sensitive area of the SSPD is patterned using the photon-number-resolving design and occupies an area of 40×40 μm2. Using this approach, we have obtained excellent specifications: system detection efficiency of 47% measured using a 900 nm laser and low dark count rate of 100 cps. The main advantages of the approach presented are a very short dead time of the detector of 22 ns and FWHM jitter value of about 130 ps.
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ISSN 1742-6588 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1224
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Author Moshkova, M. A.; Divochiy, A. V.; Morozov, P. V.; Antipov, A. V.; Vakhtomin, Yu. B.; Smirnov, K. V.
Title Characterization of topologies of superconducting photon number resolving detectors Type Conference Article
Year 2019 Publication Proc. 8th Int. Conf. Photonics and Information Optics Abbreviated Journal Proc. 8th Int. Conf. Photonics and Information Optics
Volume Issue Pages (down) 465-466
Keywords PNR SSPD
Abstract Comparative analysis for different topologies of superconducting single-photon detectors with ability to resolve up to 4 photons in a short pulse of IR radiation has been carry out. It was developed the detector with a system detection efficiency of ~ 85 % at λ = 1550 nm. The possibility of using such detector to restore photon statistics of a pulsed radiation source was demonstrated.
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Language Russian Summary Language Original Title
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ISSN ISBN 978-5-7262-2536-4 Medium
Area Expedition Conference
Notes http://fioconf.mephi.ru/files/2018/12/FIO2019-Sbornik.pdf Approved no
Call Number Serial 1803
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Author Moshkova, M.; Divochiy, A.; Morozov, P.; Vakhtomin, Y.; Antipov, A.; Zolotov, P.; Seleznev, V.; Ahmetov, M.; Smirnov, K.
Title High-performance superconducting photon-number-resolving detectors with 86% system efficiency at telecom range Type Journal Article
Year 2019 Publication J. Opt. Soc. Am. B Abbreviated Journal J. Opt. Soc. Am. B
Volume 36 Issue 3 Pages (down) B20
Keywords NbN PNR SSPD, SNSPD
Abstract The use of improved fabrication technology, highly disordered NbN thin films, and intertwined section topology makes it possible to create high-performance photon-number-resolving superconducting single-photon detectors (PNR SSPDs) that are comparable to conventional single-element SSPDs at the telecom range. The developed four-section PNR SSPD has simultaneously an 86±3% system detection efficiency, 35 cps dark count rate, ∼2 ns dead time, and maximum 90 ps jitter. An investigation of the PNR SSPD’s detection efficiency for multiphoton events shows good uniformity across sections. As a result, such a PNR SSPD is a good candidate for retrieving the photon statistics for light sources and quantum key distribution systems.
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Series Volume Series Issue Edition
ISSN 0740-3224 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1225
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