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Author Lusche, Robert; Semenov, Alexey; Huebers, Heinz-Willhelm; Ilin, Konstantin; Siegel, Michael; Korneeva, Yuliya; Trifonov, Andrey; Korneev, Alexander; Goltsman, Gregory
Title Effect of the wire geometry and an externally applied magnetic field on the detection efficiency of superconducting nanowire single-photon detectors Type Abstract
Year 2013 Publication INIS Abbreviated Journal INIS
Volume (down) 46 Issue 8 Pages 1-3
Keywords TaN, NbN SSPD, SNSPD
Abstract The interest in single-photon detectors in the near-infrared wavelength regime for applications, e.g. in quantum cryptography has immensely increased in the last years. Superconducting nanowire single-photon detectors (SNSPD) already show quite reasonable detection efficiencies in the NIR which can even be further improved. Novel theoretical approaches including vortex-assisted photon counting state that the detection efficiency in the long wavelength region can be enhanced by the detector geometry and an applied magnetic field. We present spectral measurements in the wavelength range from 350-2500 nm of the detection efficiency of meander-type TaN and NbN SNSPD with varying nanowire line width from 80 to 250 nm. Due to the used experimental setup we can accurately normalize the measured spectra and are able to extract the intrinsic detection efficiency (IDE) of our detectors. The results clearly indicate an improvement of the IDE depending on the wire width according to the theoretic models. Furthermore we experimentally found that the smallest detectable photon-flux can be increased by applying a small magnetic field to the detectors.
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Notes Approved no
Call Number Serial 1374
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Author Il'in, K. S.; Karasik, B. S.; Ptitsina, N. G.; Sergeev, A. V.; Gol'tsman, G. N.; Gershenzon, E. M.; Pechen, E. V.; Krasnosvobodtsev, S. I.
Title Electron-phonon-impurity interference in thin NbC films: electron inelastic scattering time and corrections to resistivity Type Conference Article
Year 1996 Publication Czech. J. Phys. Abbreviated Journal Czech. J. Phys.
Volume (down) 46 Issue S2 Pages 857-858
Keywords NbC films
Abstract Complex study of transport properties of impure NbC films with the electron mean free pathl=0.6–13 nm show the crucial role of the electron-phonon-impurity interference (EPII). In the temperature range 20–70 K we found the interference correction to resistivity proportional to T2 and to the residual resistivity of the film. Using the comprehensive theory of EPII, we determine the electron coupling with transverse phonons and calculate the electron inelastic scattering time. Direct measurements of the inelastic electron scattering time using a response to a high-frequency amplitude modulated cw radiation agree well with the theory.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0011-4626 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1617
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Author Chulcova, G. M.; Ptitsina, N. G.; Gershenzon, E. M.; Gershenzon, M. E.; Sergeev, A. V.
Title Effect of the interference between electron-phonon and electron-impurity (boundary) scattering on resistivity Nb, Al, Be films Type Conference Article
Year 1996 Publication Czech J. Phys. Abbreviated Journal Czech J. Phys.
Volume (down) 46 Issue S5 Pages 2489-2490
Keywords Al, Be, Nb films
Abstract The temperature dependence of the resistivity of thin Nb, Al, Be films has been studied over a wide temperature range 4-300 K. We have found that the temperature-dependent correction to the residual resistivity is well described by the sum of the Bloch-Grüneisen term and the term originating from the interference between electron-phonon and electron-impurity scattering. Study of the transport interference phenomena allows to determine electron-phonon coupling in disordered metals. The interference term is proportional to T2 and also to the residual resistivity and dominates over the Bloch-Grüneisen term at low temperatures (T<40 K).
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ISSN 0011-4626 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1767
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Author Beck, Matthias; Leiderer, Paul; Kabanov, Viktor V.; Gol'tsman, Gregory; Helm, Manfred; Demsar, Jure
Title Energy-gap dynamics of a superconductor NbN studied by time-resolved terahertz spectroscopy Type Abstract
Year 2012 Publication INIS Abbreviated Journal INIS
Volume (down) 45 Issue 12 Pages 1-3
Keywords NbN energy gap
Abstract Using time-resolved terahertz (THz) spectroscopy we performed direct studies of the photoinduced suppression and recovery of the SC gap in a conventional SC NbN. Both processes are found to be strongly temperature and excitation density dependent. The analysis of the data with the established phenomenological Rothwarf-Taylor model enabled us to determine the important microscopic constants: the Cooper pair-breaking rate via phonon absorption and the bare quasiparticle recombination rate. From the latter we were able to extract the dimensionless electron-phonon coupling constant, λ=1.1±0.1, in excellent agreement with theoretical estimates. The technique also allowed us to determine the absorbed energy required to suppress SC, which in NbN equals the thermodynamic condensation energy (in cuprates the two differ by an order of magnitude). Finally, we present the first studies of dynamics following resonant excitation with intense narrow band THz pulses tuned to above and below the superconducting gap. These suggest an additional process, particularly pronounced near Tc, that could be attributed to amplification of SC via effective quasiparticle cooling.
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Notes Approved no
Call Number Serial 1383
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Author Milostnaya, I.; Korneev, A.; Rubtsova, I.; Seleznev, V.; Minaeva, O.; Chulkova, G.; Okunev, O.; Voronov, B.; Smirnov, K.; Gol'tsman, G.; Slysz, W.; Wegrzecki, M.; Guziewicz, M.; Bar, J.; Gorska, M.; Pearlman, A.; Kitaygorsky, J.; Cross, A.; Sobolewski, R.
Title Superconducting single-photon detectors designed for operation at 1.55-µm telecommunication wavelength Type Conference Article
Year 2006 Publication J. Phys.: Conf. Ser. Abbreviated Journal J. Phys.: Conf. Ser.
Volume (down) 43 Issue Pages 1334-1337
Keywords NbN SSPD, SNSPD
Abstract We report on our progress in development of superconducting single-photon detectors (SSPDs), specifically designed for secure high-speed quantum communications. The SSPDs consist of NbN-based meander nanostructures and operate at liquid helium temperatures. In general, our devices are capable of GHz-rate photon counting in a spectral range from visible light to mid-infrared. The device jitter is 18 ps and dark counts can reach negligibly small levels. The quantum efficiency (QE) of our best SSPDs for visible-light photons approaches a saturation level of ~30-40%, which is limited by the NbN film absorption. For the infrared range (1.55µm), QE is ~6% at 4.2 K, but it can be significantly improved by reduction of the operation temperature to the 2-K level, when QE reaches ~20% for 1.55-µm photons. In order to further enhance the SSPD efficiency at the wavelength of 1.55 µm, we have integrated our detectors with optical cavities, aiming to increase the effective interaction of the photon with the superconducting meander and, therefore, increase the QE. A successful effort was made to fabricate an advanced SSPD structure with an optical microcavity optimized for absorption of 1.55 µm photons. The design consisted of a quarter-wave dielectric layer, combined with a metallic mirror. Early tests performed on relatively low-QE devices integrated with microcavities, showed that the QE value at the resonator maximum (1.55-µm wavelength) was of the factor 3-to-4 higher than that for a nonresonant SSPD. Independently, we have successfully coupled our SSPDs to single-mode optical fibers. The completed receivers, inserted into a liquid-helium transport dewar, reached ~1% system QE for 1.55 µm photons. The SSPD receivers that are fiber-coupled and, simultaneously, integrated with resonators are expected to be the ultimate photon counters for optical quantum communications.
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ISSN 1742-6588 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1450
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Author Gershenzon, E.; Goltsman, G.; Elantev, A.; Kagane, M.
Title Energy-spectrum of small donors and acceptors in germanium and effect of magnetic-field on it Type Conference Article
Year 1978 Publication Izv. Akad. Nauk SSSR, Seriya Fizicheskaya Abbreviated Journal Izv. Akad. Nauk SSSR, Seriya Fizicheskaya
Volume (down) 42 Issue 6 Pages 1142-1148
Keywords energy spectrum, Ge, magnetic field
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Notes Approved no
Call Number Serial 1722
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Author Gershenzon, E.; Goltsman, G.; Orlov, L.; Ptitsina, N.
Title Population of excited-states of small admixtures in germanium Type Conference Article
Year 1978 Publication Izv. Akad. Nauk SSSR, Seriya Fizicheskaya Abbreviated Journal Izv. Akad. Nauk SSSR, Seriya Fizicheskaya
Volume (down) 42 Issue 6 Pages 1154-1159
Keywords Ge, excited states, admixtures
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Publisher Mezhdunarodnaya Kniga 39 Dimitrova Ul., 113095 Moscow, Russia Place of Publication Editor
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Area Expedition Conference
Notes Approved no
Call Number Serial 1723
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Author Blagosklonskaya, L. E.; Gershenzon, E. M.; Goltsman, G. N.; Elantev, A. I.
Title Effect of strong magnetic-field on spectrum of hydrogen-like admixtures in semiconductors Type Conference Article
Year 1978 Publication Izv. Akad. Nauk SSSR, Seriya Fizicheskaya Abbreviated Journal Izv. Akad. Nauk SSSR, Seriya Fizicheskaya
Volume (down) 42 Issue 6 Pages 1231-1234
Keywords spectrum, semiconductors, admixtures, strong magnetic-field
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Publisher Mezhdunarodnaya Kniga 39 Dimitrova Ul., 113095 Moscow, Russia Place of Publication Editor
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Notes Approved no
Call Number blagosklonskaya1978effect Serial 1724
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Author Slysz, W.; Wegrzecki, M.; Bar, J.; Grabiec, P.; Gol'tsman, G. N.; Verevkin, M.; Sobolewski, R.
Title NbN superconducting single-photon detectors coupled with a communication fiber Type Miscellaneous
Year 2004 Publication INIS Abbreviated Journal INIS
Volume (down) 37 Issue 2 Pages 1-2
Keywords NbN SSPD, SNSPD
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Address Stare Jablonki, Poland
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Area Expedition Conference 8-th Electron Technology Conference ELTE
Notes Approved no
Call Number Serial 1486
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Author Slysz, W.; Wegrzecki, M.; Papis, E.; Gol'tsman, G. N.; Verevkin, A.; Sobolewski, R.
Title A method of optimization of the NbN superconducting single-photon detector Type Miscellaneous
Year 2004 Publication INIS Abbreviated Journal INIS
Volume (down) 36 Issue 27 Pages 1-2
Keywords NbN SSPD, SNSPD
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Area Expedition Conference 5-th International Symposium Ion Implantation and Other Applications of Ions and Electrons, ION
Notes Reference num. 36060124 Approved no
Call Number Serial 1485
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