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Author Murphy, A.; Semenov, A.; Korneev, A.; Korneeva, Y.; Gol’tsman, G.; Bezryadin, A.
Title Dark counts initiated by macroscopic quantum tunneling in NbN superconducting photon detectors Type Miscellaneous
Year 2014 Publication arXiv Abbreviated Journal
Volume Issue (up) Pages
Keywords NbN SSPD
Abstract We perform measurements of the switching current distributions of three w = 120 nm wide, 4 nm thick NbN superconducting strips which are used for single-photon detectors. These strips are much wider than the diameter the vortex cores, so they are classified as quasi-two-dimensional (quasi-2D). We discover evidence of macroscopic quantum tunneling by observing the saturation of the standard deviation of the switching distributions at temperatures around 2 K. We analyze our results using the Kurkijarvi-Garg model and find that the escape temperature also saturates at low temperatures, confirming that at sufficiently low temperatures, macroscopic quantum tunneling is possible in quasi-2D strips and can contribute to dark counts observed in single photon detectors.
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Call Number murphy2014dark Serial 1356
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Author Korneev, A.; Korneeva, Y.; Florya, I.; Voronov, B.; Goltsman, G.
Title Spectral sensitivity of narrow strip NbN superconducting single-photon detector Type Conference Article
Year 2011 Publication Proc. SPIE Abbreviated Journal Proc. SPIE
Volume 8072 Issue (up) Pages 80720G (1 to 9)
Keywords NbN SSPD, SNSPD
Abstract Superconducting single-photon detector (SSPD) is patterned from 4-nm-thick NbN film deposited on sapphire substrate as a 100-nm-wide strip. Due to its high detection efficiency, low dark counts, and picosecond timing jitter SSPD has become a competitor to the InGaAs avalanche photodiodes at 1550 nm and longer wavelengths. Although the SSPD is operated at liquid helium temperature its efficient single-mode fibre coupling enabled its usage in many applications ranging from single-photon sources research to quantum cryptography. In our strive to increase the detection efficiency at 1550 nm and longer wavelengths we developed and fabricated SSPD with the strip almost twice narrower compared to the standard 100 nm. To increase the voltage response of the device we utilized cascade switching mechanism: we connected 50-nm-wide and 10-μm-long strips in parallel covering the area of 10 μmx10 μm. Absorption of a photon breaks the superconductivity in a strip leading to the bias current redistribution between other strips followed their cascade switching. As the total current of all the strips about is 1 mA by the order of magnitude the response voltage of such an SSPD is several times higher compared to the traditional meander-shaped SSPDs. In middle infrared (about 3 μm wavelength) these devices have the detection efficiency several times higher compared to the traditional SSPDs.
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Publisher SPIE Place of Publication Editor Fiurásek, J.; Prochazka, I.
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Area Expedition Conference Photon Counting Applications, Quantum Optics, and Quantum Information Transfer and Processing III
Notes Approved no
Call Number Serial 1387
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Author Dryazgov, M.; Semenov, A.; Manova, N.; Korneeva, Y.; Korneev, A.
Title Modelling of normal domain evolution after single-photon absorption of a superconducting strip of micron width Type Conference Article
Year 2020 Publication J. Phys.: Conf. Ser. Abbreviated Journal J. Phys.: Conf. Ser.
Volume 1695 Issue (up) Pages 012195 (1 to 4)
Keywords SSPD modelling, SNSPD
Abstract The present paper describes a modelling of normal domain evolution in superconducting strip of micron width using solving differential equations describing the temperature and current changes. The solving results are compared with experimental data. This comparison demonstrates the high accuracy of the model. In future, it is possible to employ this model for improvement of single photon detector based on micron-scale superconducting strips.
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ISSN 1742-6588 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1785
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Author Manova, N. N.; Simonov, N. O.; Korneeva, Y. P.; Korneev, A. A.
Title Developing of NbN films for superconducting microstrip single-photon detector Type Conference Article
Year 2020 Publication J. Phys.: Conf. Ser. Abbreviated Journal J. Phys.: Conf. Ser.
Volume 1695 Issue (up) Pages 012116 (1 to 5)
Keywords NbN SSPD, SNSPD, NbN films
Abstract We optimized NbN films on a Si substrate with a buffer SiO2 layer to produce superconducting microstrip single-photon detectors with saturated dependence of quantum efficiency (QE) versus normalized bias current. We varied thickness of films and observed the maximum QE saturation for device based on the thinner film with the lowest ratio RS300/RS20.
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ISSN 1742-6588 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1786
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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 (up) 10 Pages 104503 (1 to 9)
Keywords SSPD, SNSPD
Abstract 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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Series Volume Series Issue Edition
ISSN 1098-0121 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1343
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