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Author Swetz, D. S.; Bennett, D. A.; Irwin, K. D.; Schmidt, D. R.; Ullom, J. N. doi  openurl
  Title Current distribution and transition width in superconducting transition-edge sensors Type Journal Article
  Year 2012 Publication Appl. Phys. Lett. Abbreviated Journal Appl. Phys. Lett.  
  Volume (down) 101 Issue Pages 242603  
  Keywords  
  Abstract Present models of the superconducting-to-normal transition in transition-edge sensors (TESs) do not describe the current distribution within a biased TES. This distribution is complicated by normal-metal features that are integral to TES design. We present a model with one free parameter that describes the evolution of the current distribution with bias. To probe the current distribution experimentally, we fabricated TES devices with different current return geometries. Devices where the current return geometry mirrors current flow within the device have sharper transitions, thus allowing for a direct test of the current-flow model.Measurements from these devices show that current meanders through a TES low in the resistivetransition but flows across the normal-metal features by 40% of the normal-state resistance. Comparison of transition sharpness between device designs reveals that self-induced magnetic fields play an important role in determining the width of the superconducting transition.  
  Address TES, current distribution  
  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 Recommended by Klapwijk Approved no  
  Call Number Serial 930  
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Author Rasulova, G. K.; Brunkov, P. N.; Pentin, I. V.; Egorov, A. Y.; Knyazev, D. A.; Andrianov, A. V.; Zakhar’in, A. O.; Konnikov, S. G.; Gol’tsman, G. N. url  doi
openurl 
  Title A weakly coupled semiconductor superlattice as a potential for a radio frequency modulated terahertz light emitter Type Journal Article
  Year 2012 Publication Appl. Phys. Lett. Abbreviated Journal Appl. Phys. Lett.  
  Volume (down) 100 Issue 13 Pages 131104 (1 to 4)  
  Keywords semiconductor superlattice  
  Abstract The bolometer response to THz radiation from a weakly coupled GaAs/AlGaAs superlattice biased in the self-oscillations regime has been observed. The bolometer signal is modulated with the frequency equal to the fundamental frequency of superlattice self-oscillations. The frequency spectrum of the bolometer signal contains higher harmonics whose frequency is a multiple of fundamental frequency of self-oscillations.

This work was supported by State Contracts Nos. 16.740.11.0044 and 16.552.11.7002 of Ministry of Education and Science of the Russian Federation. Structural characterization was made on the equipment of the Joint Research Centre «Material science and characterization in advanced technology» (Ioffe Institute, St. Petersburg, Russia).
 
  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 0003-6951 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1379  
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Author Tuchak, A. N.; Gol’tsman, G. N.; Kitaeva, G. K.; Penin, A. N.; Seliverstov, S. V.; Finkel, M. I.; Shepelev, A. V.; Yakunin, P. V. url  doi
openurl 
  Title Generation of nanosecond terahertz pulses by the optical rectification method Type Journal Article
  Year 2012 Publication JETP Lett. Abbreviated Journal JETP Lett.  
  Volume (down) 96 Issue 2 Pages 94-97  
  Keywords optical rectification, lithium niobate crystal  
  Abstract The possibility of the generation of quasi-cw terahertz radiation by the optical rectification method for broad-band Fourier unlimited nanosecond laser pulses has been experimentally demonstrated. The broadband radiation of a LiF dye-center laser is used as a pump source of a nonlinear optical oscillator. The energy efficiency of terahertz optical frequency conversion in a periodically polarized lithium niobate crystal is 4 × 10−9 at a pump power density of 7 MW/cm2.  
  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 0021-3640 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1377  
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Author Steudle, Gesine A.; Schietinger, Stefan; Höckel, David; Dorenbos, Sander N.; Zadeh, Iman E.; Zwiller, Valery; Benson, Oliver doi  openurl
  Title Measuring the quantum nature of light with a single source and a single detector Type Journal Article
  Year 2012 Publication Phys. Rev. A Abbreviated Journal  
  Volume (down) 86 Issue 5 Pages 053814  
  Keywords SSPD, SNSPD, saturation count rates, dead time, dynamic range  
  Abstract An elementary experiment in optics consists of a light source and a detector. Yet, if the source generates nonclassical correlations such an experiment is capable of unambiguously demonstrating the quantum nature of light. We realized such an experiment with a defect center in diamond and a superconducting detector. Previous experiments relied on more complex setups, such as the Hanbury Brown and Twiss configuration, where a beam splitter directs light to two photodetectors, creating the false impression that the beam splitter is a fundamentally required element. As an additional benefit, our results provide a simplification of the widely used photon-correlation techniques.  
  Address  
  Corporate Author Thesis  
  Publisher American Physical Society 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 Serial 1089  
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Author Bulaevskii, L. N.; Graf, Matthias J.; Kogan, V. G. openurl 
  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 (down) 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.  
  Address  
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  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 733  
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