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Author Vasilev, D. D.; Malevannaya, E. I.; Moiseev, K. M.; Zolotov, P. I.; Antipov, A. V.; Vakhtomin, Y. B.; Smirnov, K. V.
Title Influence of deposited material energy on superconducting properties of the WSi films Type Conference Article
Year 2020 Publication IOP Conf. Ser.: Mater. Sci. Eng. Abbreviated Journal IOP Conf. Ser.: Mater. Sci. Eng.
Volume 781 Issue Pages 012013 (1 to 6)
Keywords WSi SSPD, SNSPD
Abstract (down) WSi thin films have the advantages for creating SNSPDs with a large active area or array of detectors on a single substrate due to the amorphous structure. The superconducting properties of ultrathin WSi films substantially depends on their structure and thickness as the NbN films. Scientific groups investigating WSi films mainly focused only on changes of their thickness and the ratio of the components on the substrate at room temperature. This paper presents experiments to determine the effect of the bias potential on the substrate, the temperature of the substrate, and the peak power of pulsed magnetron sputtering, which is the equivalent of ionization, a tungsten target, on the surface resistance and superconducting properties of the WSi ultrathin films. The negative effect of the substrate temperature and the positive effect of the bias potential and the ionization coefficient (peak current) allow one to choose the best WSi films formation mode for SNSPD: substrate temperature 297 K, bias potential -60 V, and peak current 3.5 A.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1757-899X ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1798
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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 (down) 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.
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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 1098-0121 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1343
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Author Baselmans, J. J. A.; Hajenius, M.; Gao, J. R.; Baryshev, A.; Kooi, J.; Klapwijk, T. M.; de Korte, P. A. J.; Voronov, B.; Gol’tsman, G.
Title Hot electron bolometer mixers with improved interfaces: sensitivity, LO power and stability Type Conference Article
Year 2004 Publication Proc. 15th Int. Symp. Space Terahertz Technol. Abbreviated Journal Proc. 15th Int. Symp. Space Terahertz Technol.
Volume Issue Pages 17-24
Keywords NbN HEB mixers
Abstract (down) We study twin slot antenna coupled NbN hot electron bolometer mixers with an improved contact structure and a small volume, ranging from 1 µm × 0.1 µm to 2 × 0.3 µm. We obtain a DSB receiver noise temperature of 900 K at 1.6 THz and 940 K at 1.9 THz. To explore the practical usability of such small HEB mixers we evaluate the LO power requirement, the sensitivity and the stability. We find that the LO power requirement of the smallest mixers is reduced to about 240 nW at the Si lens of the mixer. This value is larger than expected from the isothermal technique and the known losses in the lens by a factor of 3-3.5. The stability of these receivers is characterized using a measurement of the Allan Variance. We find an Allan time of 0.5 sec. in an 80 MHz bandwidth. A small increase in stability can be reached by using a higher bias at the expense of a significant amount of sensitivity. The stability is sufficient for spectroscopic applications in a 1 MHz bandwidth at a 1 Hz chopping frequency.
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Series Editor Series Title Abbreviated Series Title
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ISSN ISBN Medium
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Notes Approved no
Call Number Serial 1491
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Author Kuznetsov, K. A.; Kornienko, V. V.; Vakhtomin, Y. B.; Pentin, I. V.; Smirnov, K. V.; Kitaeva, G. K.
Title Generation and detection of optical-terahertz biphotons via spontaneous parametric downconversion Type Conference Article
Year 2018 Publication Proc. ICLO Abbreviated Journal Proc. ICLO
Volume Issue Pages 303
Keywords NbN HEB applications
Abstract (down) We study spontaneous parametric downconversion (SPDC) in the strongly non-degenerate regime when the idler wave hits the terahertz range. By using the hot-electron bolometer, for the first time the SPDC-generated idler-wave photons were directly detected in the terahertz frequency range. Spectrum of corresponding signal photons was measured using standard technique by the CCD camera. Possible applications of correlated optical-terahertz biphotons are discussed.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
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ISSN ISBN Medium
Area Expedition Conference International Conference Laser Optics
Notes Approved no
Call Number Serial 1806
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Author Korneev, A.; Korneeva, Y.; Florya, I.; Semenov, A.; Goltsman, G.
Title Photon switching statistics in multistrip superconducting single-photon detectors Type Journal Article
Year 2018 Publication IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.
Volume 28 Issue 7 Pages 1-4
Keywords SSPD, SNSPD
Abstract (down) We study photon count statistics in superconducting single-photon detectors consisting of up to 70 narrow superconducting strips connected in parallel. Using interarrival time analysis, we demonstrate that our samples are operated in the “arm-trigger” regime and require up to seven subsequently absorbed photons to form a resistive state in the whole sample. We also performed numerical simulation of the light and dark count rates versus detector bias current, which are in good agreement with the experimental results.
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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 1051-8223 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1304
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