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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 | |||
| Call Number | RPLAB @ gujma @ | Serial  |
733 | ||
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| Author | Henrich, D.; Dorner,S.; Hofherr, M.; Il'in, K.; Semenov, A.; Heintze, E.; Scheffler, M.; Dressel, M.; Siegel, M. | ||||
| Title | Broadening of hot-spot response spectrum of superconducting NbN nanowire single-photon detector with reduced nitrogen content | Type | Journal Article | ||
| Year | 2012 | Publication | Abbreviated Journal | J. Appl. Phys. | |
| Volume | 112 | Issue | Pages | ||
| Keywords | SSPD, SNSPD, magnetron sputtering, spectrum, NbN film, nitrogen concentration | ||||
| Abstract | The spectral detection efficiency and the dark count rate of superconducting nanowire single-photon detectors (SNSPD) have been studied systematically on detectors made from thin NbN films with different chemical compositions. Reduction of the nitrogen content in the 4 nm thick NbN films results in a decrease of the dark count rates more than two orders of magnitude and in a red shift of the cut-off wavelength of the hot-spot SNSPD response. The observed phenomena are explained by an improvement of uniformity of NbN films that has been confirmed by a decrease of resistivity and an increase of the ratio of the measured critical current to the depairing current. The latter factor is considered as the most crucial for both the cut-off wavelength and the dark count rates of SNSPD. Based on our results we propose a set of criteria for material properties to optimize SNSPD in the infrared spectral region. VC 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4757625] |
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| Corporate Author | D. Henrich, S. Dorner, M. Hofherr, K. Il'in, A. Semenov, E. Heintze, M. Scheffler, M. Dressel, M. Siegel | Thesis | |||
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| Language | English | Summary Language | Original Title | Broadening of hot-spot response spectrum of superconducting NbN nanowire single-photon detector with reduced nitrogen content | |
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| Notes | Approved | no | |||
| Call Number | RPLAB @ seleznev @ | Serial |
877 | ||
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| Author | Inderbitzin, K.; Engel, A.; Schilling, A.; Il'in, K.; Siegel, M. | ||||
| Title | An ultra-fast superconducting Nb nanowire single-photon detector for soft x-rays | Type | Journal Article | ||
| Year | 2012 | Publication | Abbreviated Journal | Appl. Phys. Lett. | |
| Volume | 101 | Issue | Pages | ||
| Keywords | SSPD, SNSPD, x-ray, Nb | ||||
| Abstract | Although superconducting nanowire single-photon detectors (SNSPDs) are well studied regarding the detection of infrared/optical photons and keV-molecules, no studies on continuous x-ray photon counting by thick-film detectors have been reported so far. We fabricated a 100 nm thick niobium x-ray SNSPD (an X-SNSPD) and studied its detection capability of photons with keV-energies in continuous mode. The detector is capable to detect photons even at reduced bias currents of 0.4%, which is in sharp contrast to optical thin-film SNSPDs. No dark counts were recorded in extended measurement periods. Strikingly, the signal amplitude distribution depends significantly on the photon energy spectrum.VC |
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| Notes | Approved | no | |||
| Call Number | RPLAB @ seleznev @ | Serial |
878 | ||
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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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| Series Volume | Series Issue | Edition | |||
| ISSN | 1062-8738 | ISBN | Medium | ||
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| Notes | Approved | no | |||
| Call Number | RPLAB @ kovalyuk @ | Serial |
940 | ||
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| Author | Korneev, A. A.; Korneeva, Y. P.; Mikhailov, M. Yu.; Pershin, Y. P.; Semenov, A. V.; Vodolazov, D. Yu.; Divochiy, A. V.; Vakhtomin, Y. B.; Smirnov, K. V.; Sivakov, A. G.; Devizenko, A. Yu.; Goltsman, G. N. | ||||
| Title | Characterization of MoSi superconducting single-photon detectors in the magnetic field | Type | Journal Article | ||
| Year | 2015 | Publication | IEEE Trans. Appl. Supercond. | Abbreviated Journal | IEEE Trans. Appl. Supercond. |
| Volume | 25 | Issue | 3 | Pages | 2200504 (1 to 4) |
| Keywords | SSPD, SNSPD | ||||
| Abstract | We investigate the response mechanism of nanowire superconducting single-photon detectors (SSPDs) made of amorphous MoxSi1-x. We study the dependence of photon count and dark count rates on bias current in magnetic fields up to 113 mT at 1.7 K temperature. The observed behavior of photon counts is similar to the one recently observed in NbN SSPDs. Our results show that the detecting mechanism of relatively high-energy photons does not involve the vortex penetration from the edges of the film, and on the contrary, the detecting mechanism of low-energy photons probably involves the vortex penetration from the film edges. | ||||
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| Notes | Approved | no | |||
| Call Number | RPLAB @ akorneev @ KorneevIEEE2015 | Serial |
991 | ||
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