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| Author | Bulaevskii, L. N.; Graf, Matthias J.; Kogan, V. G. | ||||
| Title | Vortex-assisted photon counts and their magnetic field dependence in single-photon superconducting detectors | Type | Journal Article | ||
| Year | 2012 | Publication | Phys. Rev. B | Abbreviated Journal | Phys. Rev. B |
| Volume | 85 | Issue | 1 | Pages | 9 |
| Keywords | SSPD; SNSPD; single-vortex crossing; normal-state belt | ||||
| Abstract | We argue that photon counts in a superconducting nanowire single-photon detector (SNSPD) are caused by the transition from a current-biased metastable superconducting state to the normal state. Such a transition is triggered by vortices crossing the thin and narrow superconducting strip from one edge to another due to the Lorentz force. Detector counts in SNSPDs may be caused by three processes: (a) a single incident photon with sufficient energy to break enough Cooper pairs to create a normal-state belt across the entire width of the strip (direct photon count), (b) thermally induced single-vortex crossing in the absence of photons (dark count), which at high-bias currents releases the energy sufficient to trigger the transition to the normal state in a belt across the whole width of the strip, and (c) a single incident photon of insufficient energy to create a normal-state belt but initiating a subsequent single-vortex crossing, which provides the rest of the energy needed to create the normal-state belt (vortex-assisted single-photon count). We derive the current dependence of the rate of vortex-assisted photon counts. The resulting photon count rate has a plateau at high currents close to the critical current and drops as a power law with high exponent at lower currents. While the magnetic field perpendicular to the film plane does not affect the formation of hot spots by photons, it causes the rate of vortex crossings (with or without photons) to increase. We show that by applying a magnetic field one may characterize the energy barrier for vortex crossings and identify the origin of dark counts and vortex-assisted photon counts. | ||||
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| Notes | Approved | no | |||
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RPLAB @ gujma @ | Serial | 733 | ||
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| Author | Чулкова, Г. М.; Семенов, А. В.; Корнеев, А. А.; Кардакова, А. И.; Аверьев, Н. В.; Ан, П. П.; Казаков, А. Ю.; Трифонов, А. В. | ||||
| Title | Спектральная чувствительность сверхпроводникового однофотонного детектора | Type | Journal Article | ||
| Year | 2011 | Publication | Журнал радиоэлектроники | Abbreviated Journal | Ж. радиоэлектрон. |
| Volume | 11 | Issue | Pages | 5 | |
| Keywords | SSPD; quantum efficiency; spectral sensitivity | ||||
| Abstract | We consider quantum efficiency dependence on photons' energy from hot spot model. Direction of quasiparticles diffusion drive across superconductive film. The maximal quantum efficiency is proportional to a probability of photon absorption. The spectral sensitivity of superconductive single photon detector does not have clearly expressed red limit. Changing regimes of work depends on a wavelength we can get high values of quantum efficiency in visible and infrared range which will be specified by the quality of fabrication of detectors and their consistency with the radiation. Key words: superconducting single-photon detector, SSPD, quantum efficiency, spectral sensitivity. В статье представлена зависимость квантовой эффективности от энергии фотона в рамках модели горячего пятна. Диффузия квазичастиц происходит в основном перпендикулярно направлению тока в областях с максимальной плотностью тока. Максимальная квантовая эффективность детектора пропорциональна вероятности поглощения фотона. Несмотря на квантовый характер работы сверхпроводникового однофотонного детектора, он не имеет четко выраженной красной границы. Изменяя режим работы в зависимости от длины волны можно в видимом и инфракрасном диапазонах получать высокие значения квантовой эффективности, которые будут определяться лишь качеством изготовления детекторов и степенью их согласования с излучением. |
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| Notes | Approved | no | |||
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RPLAB @ gujma @ | Serial | 844 | ||
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| Author | Ferrari, S.; Kovalyuk, V.; Hartmann, W.; Vetter, A.; Kahl, O.; Lee, C.; Korneev, A.; Rockstuhl, C.; Gol'tsman, G.; Pernice, W. | ||||
| Title | Hot-spot relaxation time current dependence in niobium nitride waveguide-integrated superconducting nanowire single-photon detectors | Type | Journal Article | ||
| Year | 2017 | Publication | Opt. Express | Abbreviated Journal | Opt. Express |
| Volume | 25 | Issue | 8 | Pages | 8739-8750 |
| Keywords | SSPD, SNSPD, photon counting; Infrared; Quantum detectors; Integrated optics; Multiphoton processes; Photon statistics | ||||
| Abstract | We investigate how the bias current affects the hot-spot relaxation dynamics in niobium nitride. We use for this purpose a near-infrared pump-probe technique on a waveguide-integrated superconducting nanowire single-photon detector driven in the two-photon regime. We observe a strong increase in the picosecond relaxation time for higher bias currents. A minimum relaxation time of (22 +/- 1)ps is obtained when applying a bias current of 50% of the switching current at 1.7 K bath temperature. We also propose a practical approach to accurately estimate the photon detection regimes based on the reconstruction of the measured detector tomography at different bias currents and for different illumination conditions. | ||||
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| Notes | Approved | no | |||
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RPLAB @ kovalyuk @ | Serial | 1118 | ||
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| Author | Glejm, A. V.; Anisimov, A. A.; Asnis, L. N.; Vakhtomin, Yu. B.; Divochiy, A. V.; Egorov, V. I.; Kovalyuk, V. V.; Korneev, A. A.; Kynev, S. M.; Nazarov, Yu. V.; Ozhegov, R. V.; Rupasov, A. V.; Smirnov, K. V.; Smirnov, M. A.; Goltsman, G. N.; Kozlov, S. A. | ||||
| Title | Quantum key distribution in an optical fiber at distances of up to 200 km and a bit rate of 180 bit/s | Type | Journal Article | ||
| Year | 2014 | Publication | Bulletin of the Russian Academy of Sciences. Physics | Abbreviated Journal | |
| Volume | 78 | Issue | 3 | Pages | 171-175 |
| Keywords | SSPD, SNSPD, applications | ||||
| Abstract | An experimental demonstration of a subcarrier-wave quantum cryptography system with superconducting single-photon detectors (SSPDs) that distributes a secure key in a single-mode fiber at distance of 25 km with a bit rate of 800 kbit/s, a distance of 100 km with a bit rate of 19 kbit/s, and a distance of 200 km with a bit rate of 0.18 kbit/s is described. | ||||
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| ISSN | 1062-8738 | ISBN | Medium | ||
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| Notes | Approved | no | |||
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RPLAB @ kovalyuk @ | Serial | 940 | ||
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| Author | Kahl, O.; Ferrari, S.; Kovalyuk, V.; Goltsman, G. N.; Korneev, A.; Pernice, W. H. P. | ||||
| Title | Waveguide integrated superconducting single-photon detectors with high internal quantum efficiency at telecom wavelengths | Type | Journal Article | ||
| Year | 2015 | Publication | Sci. Rep. | Abbreviated Journal | Sci. Rep. |
| Volume | 5 | Issue | Pages | 10941 (1 to 11) | |
| Keywords | optical waveguides; waveguide integrated SSPD; waveguide SSPD; nanophotonics | ||||
| Abstract | Superconducting nanowire single-photon detectors (SNSPDs) provide high efficiency for detecting individual photons while keeping dark counts and timing jitter minimal. Besides superior detection performance over a broad optical bandwidth, compatibility with an integrated optical platform is a crucial requirement for applications in emerging quantum photonic technologies. Here we present efficiencies close to unity at 1550nm wavelength. This allows for the SNSPDs to be operated at bias currents far below the critical current where unwanted dark count events reach milli-Hz levels while on-chip detection efficiencies above 70% are maintained. The measured dark count rates correspond to noiseequivalent powers in the 10–19W/Hz–1/2 range and the timing jitter is as low as 35ps. Our detectors are fully scalable and interface directly with waveguide-based optical platforms. | ||||
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| Notes | PMID:26061283; PMCID:PMC4462017 | Approved | no | ||
| Call Number |
RPLAB @ kovalyuk @ | Serial | 946 | ||
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