|   | 
Details
   web
Records
Author Sidorova, M.; Semenov, A.; Hübers, H.-W.; Kuzmin, A.; Doerner, S.; Ilin, K.; Siegel, M.; Charaev, I.; Vodolazov, D.
Title Timing jitter in photon detection by straight superconducting nanowires: Effect of magnetic field and photon flux Type Journal Article
Year 2018 Publication (up) Phys. Rev. B Abbreviated Journal Phys. Rev. B
Volume 98 Issue 13 Pages 134504 (1 to 14)
Keywords SNSPD, NbN namowires
Abstract We studied the effects of the external magnetic field and photon flux on timing jitter in photon detection by straight superconducting NbN nanowires. At two wavelengths 800 and 1560 nm, statistical distribution in the appearance times of photon counts exhibits Gaussian shape at small times and an exponential tail at large times. The characteristic exponential time is larger for photons with smaller energy and increases with external magnetic field while variations in the Gaussian part of the distribution are less pronounced. Increasing photon flux drives the nanowire from the discrete quantum detection regime to the uniform bolometric regime that averages out fluctuations of the total number of nonequilibrium electrons created by the photon and drastically reduces jitter. The difference between standard deviations of Gaussian parts of distributions for these two regimes provides the measure for the strength of electron-number fluctuations; it increases with the photon energy. We show that the two-dimensional hot-spot detection model explains qualitatively the effect of magnetic field.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9950 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1842
Permanent link to this record
 

 
Author Beck, M.; Klammer, M.; Lang, S.; Leiderer, P.; Kabanov, V. V.; Gol'tsman, G. N.; Demsar, J.
Title Energy-gap dynamics of superconducting NbN thin films studied by time-resolved terahertz spectroscopy Type Journal Article
Year 2011 Publication (up) Phys. Rev. Lett. Abbreviated Journal Phys. Rev. Lett.
Volume 107 Issue 17 Pages 4
Keywords NbN thin film, energy gap dynamics
Abstract Using time-domain terahertz spectroscopy we performed direct studies of the photoinduced suppression and recovery of the superconducting gap in a conventional BCS superconductor 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 bare quasiparticle recombination rate, the Cooper pair-breaking rate and the electron-phonon coupling constant, λ=1.1±0.1, which is in excellent agreement with theoretical estimates.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number RPLAB @ gujma @ Serial 641
Permanent link to this record
 

 
Author Beck, M.; Rousseau, I.; Klammer, M.; Leiderer, P.; Mittendorff, M.; Winnerl, S.; Helm, M.; Gol'tsman, G.N.; Demsar, J.
Title Transient increase of the energy gap of superconducting NbN thin films excited by resonant narrow-band terahertz pulses Type Journal Article
Year 2013 Publication (up) Phys. Rev. Lett. Abbreviated Journal Phys. Rev. Lett.
Volume 110 Issue 26 Pages 267003 (1 to 5)
Keywords NbN thin films, energy gap
Abstract Observations of radiation-enhanced superconductivity have thus far been limited to a few type-I superconductors (Al, Sn) excited at frequencies between the inelastic scattering rate and the superconducting gap frequency 2Delta/h. Utilizing intense, narrow-band, picosecond, terahertz pulses, tuned to just below and above 2Delta/h of a BCS superconductor NbN, we demonstrate that the superconducting gap can be transiently increased also in a type-II dirty-limit superconductor. The effect is particularly pronounced at higher temperatures and is attributed to radiation induced nonthermal electron distribution persisting on a 100 ps time scale.
Address Department of Physics and Center for Applied Photonics, University of Konstanz, D-78457, Germany
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0031-9007 ISBN Medium
Area Expedition Conference
Notes PMID:23848912 Approved no
Call Number Serial 1370
Permanent link to this record
 

 
Author Gol'tsman, G. N.; Korneev, A.; Rubtsova, I.; Milostnaya, I.; Chulkova, G.; Minaeva, O.; Smirnov, K.; Voronov, B.; Słysz, W.; Pearlman, A.; Verevkin, A.; Sobolewski, R.
Title Ultrafast superconducting single-photon detectors for near-infrared-wavelength quantum communications Type Journal Article
Year 2005 Publication (up) Phys. Stat. Sol. (C) Abbreviated Journal Phys. Stat. Sol. (C)
Volume 2 Issue 5 Pages 1480-1488
Keywords NbN SSPD, SNSPD
Abstract We present our progress on the research and development of NbN superconducting single‐photon detectors (SSPD's) for ultrafast counting of near‐infrared photons for secure quantum communications. Our SSPD's operate in the quantum detection mode based on the photon‐induced hotspot formation and subsequent development of a transient resistive barrier across an ultrathin and submicron‐width superconducting stripe. The devices are fabricated from 4‐nm‐thick NbN films and kept in the 4.2‐ to 2‐K temperature range. The detector experimental quantum efficiency in the photon‐counting mode reaches above 40% for the visible light and up to 30% in the 1.3‐ to 1.55‐µm wavelength range with dark counts below 0.01 per second. The experimental real‐time counting rate is above 2 GHz and is limited by our readout electronics. The SSPD's timing jitter is below 18 ps, and the best‐measured value of the noise‐equivalent power (NEP) is 5 × 10–21 W/Hz1/2 at 1.3 µm. In terms of quantum efficiency, timing jitter, and maximum counting rate, our NbN SSPD's significantly outperform semiconductor avalanche photodiodes and photomultipliers in the 1.3‐ to 1.55‐µm range.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1610-1634 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1479
Permanent link to this record
 

 
Author Antipov, S. V.; Svechnikov, S. I.; Smirnov, K. V.; Vakhtomin, Y. B.; Finkel, M. I.; Goltsman, G. N.; Gershenzon, E. M.
Title Noise temperature of quasioptical NbN hot electron bolometer mixers at 900 GHz Type Journal Article
Year 2001 Publication (up) Physics of Vibrations Abbreviated Journal Physics of Vibrations
Volume 9 Issue 4 Pages 242-245
Keywords NbN HEB mixers
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1069-1227 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1550
Permanent link to this record