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Author (up) Huebers, Heinz-Wilhelm; Pavlov, S.; Semenov, A.; Köhler, R.; Mahler, L.; Tredicucci, A.; Beere, H.; Ritchie, D.; Linfield, E. openurl 
  Title Terahertz quantum cascade laser as local oscillator in a heterodyne receiver Type Journal Article
  Year 2005 Publication Optics Express Abbreviated Journal  
  Volume 13 Issue 15 Pages 5890-5896  
  Keywords QCL heterodyne, 6 mW at 2.5 THz, HEB mixer, terahertz  
  Abstract Terahertz quantum cascade lasers have been investigated with respect to their performance as a local oscillator in a heterodyne receiver. The beam profile has been measured and transformed in to a close to Gaussian profile resulting in a good matching between the field patterns of the quantum cascade laser and the antenna of a superconducting hot electron bolometric mixer. Noise temperature measurements with the hot electron bolometer and a 2.5 THz quantum cascade laser yielded the same result as with a gas laser as local oscillator.  
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  Notes Approved no  
  Call Number Serial 627  
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Author (up) Il'in, K.; Siegel, M.; Semenov, A.; Engel, A.; Hübers, H.-W.; Hollmann, E.; Gol'tsman, G.; Voronov, B. url  openurl
  Title Thickness dependence of superconducting properties of ultrathin Nb and NbN films Type Conference Article
  Year 2004 Publication AKF-Frühjahrstagung Abbreviated Journal  
  Volume Issue Pages  
  Keywords Nb, NbN films, has potential plagiarism  
  Abstract  
  Address Berlin-Adlershof  
  Corporate Author Thesis  
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  Series Editor Series Title Abbreviated Series Title  
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  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1503  
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Author (up) Kardakova, A.; Shishkin, A.; Semenov, A.; Goltsman, G. N.; Ryabchun, S.; Klapwijk, T. M.; Bousquet, J.; Eon, D.; Sacépé, B.; Klein, T.; Bustarret, E. url  doi
openurl 
  Title Relaxation of the resistive superconducting state in boron-doped diamond films Type Journal Article
  Year 2016 Publication Phys. Rev. B Abbreviated Journal Phys. Rev. B  
  Volume 93 Issue 6 Pages 064506  
  Keywords boron-doped diamond films, resistive superconducting state, relaxation time  
  Abstract We report a study of the relaxation time of the restoration of the resistive superconducting state in single crystalline boron-doped diamond using amplitude-modulated absorption of (sub-)THz radiation (AMAR). The films grown on an insulating diamond substrate have a low carrier density of about 2.5×1021cm−3 and a critical temperature of about 2K. By changing the modulation frequency we find a high-frequency rolloff which we associate with the characteristic time of energy relaxation between the electron and the phonon systems or the relaxation time for nonequilibrium superconductivity. Our main result is that the electron-phonon scattering time varies clearly as T−2, over the accessible temperature range of 1.7 to 2.2 K. In addition, we find, upon approaching the critical temperature Tc, evidence for an increasing relaxation time on both sides of Tc.  
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  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 1167  
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Author (up) Klapwijk, T. M.; Semenov, A. V. url  doi
openurl 
  Title Engineering physics of superconducting hot-electron bolometer mixers Type Journal Article
  Year 2017 Publication IEEE Trans. THz Sci. Technol. Abbreviated Journal IEEE Trans. THz Sci. Technol.  
  Volume 7 Issue 6 Pages 627-648  
  Keywords HEB mixers  
  Abstract Superconducting hot-electron bolometers are presently the best performing mixing devices for the frequency range beyond 1.2 THz, where good-quality superconductor-insulator-superconductor devices do not exist. Their physical appearance is very simple: an antenna consisting of a normal metal, sometimes a normal-metal-superconductor bilayer, connected to a thin film of a narrow short superconductor with a high resistivity in the normal state. The device is brought into an optimal operating regime by applying a dc current and a certain amount of local-oscillator power. Despite this technological simplicity, its operation has found to be controlled by many different aspects of superconductivity, all occurring simultaneously. A core ingredient is the understanding that there are two sources of resistance in a superconductor: a charge-conversion resistance occurring at a normal-metal-superconductor interface and a resistance due to time-dependent changes of the superconducting phase. The latter is responsible for the actual mixing process in a nonuniform superconducting environment set up by the bias conditions and the geometry. The present understanding indicates that further improvement needs to be found in the use of other materials with a faster energy relaxation rate. Meanwhile, several empirical parameters have become physically meaningful indicators of the devices, which will facilitate the technological developments.  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2156-342X ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1292  
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Author (up) Korneev, A. A.; Divochiy, A. V.; Vakhtomin, Yu. B.; Korneeva, Yu. P.; Larionov, P. A.; Manova, N. N.; Florya, I. N.; Trifonov, A. V.; Voronov, B. M.; Smirnov, K. V.; Semenov, A. V.; Chulkova, G. M.; Goltsman, G. N. url  openurl
  Title IR single-photon receiver based on ultrathin NbN superconducting film Type Journal Article
  Year 2013 Publication Rus. J. Radio Electron. Abbreviated Journal Rus. J. Radio Electron.  
  Volume Issue 5 Pages  
  Keywords SSPD, SNSPD  
  Abstract We present our recent results in research and development of superconducting single-photon detector (SSPD). We achieved the following performance improvement: first, we developed and characterized SSPD integrated in optical cavity and enabling its illumination from the face side, not through the substrate, second, we improved the quantum efficiency of the SSPD at around 3 μm wavelength by reduction of the strip width to 40 nm, and, finally, we improved the detection efficiency of the SSPD-based single-photon receiver system up to 20% at 1550 nm and extended its wavelength range beyond 1800 nm by the usage of the fluoride ZBLAN fibres.  
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  Language Russian Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
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  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes 8 pages Approved no  
  Call Number RPLAB @ sasha @ korneevir Serial 1043  
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