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Author Semenov, A. D.; Hübers, H.–W.; Schubert, J.; Gol'tsman, G. N.; Elantiev, A. I.; Voronov, B. M.; Gershenzon, E. M. url  openurl
  Title Frequency dependent noise temperature of the lattice cooled hot-electron terahertz mixer Type Conference Article
  Year 2000 Publication Proc. 11th Int. Symp. Space Terahertz Technol. Abbreviated Journal Proc. 11th Int. Symp. Space Terahertz Technol.  
  Volume Issue Pages 39-48  
  Keywords NbN HEB mixers  
  Abstract We present the measurements and the theoretical model on the frequency dependent noise temperature of a lattice cooled hot electron bolometer (HEB) mixer in the terahertz frequency range. The experimentally observed increase of the noise temperature with frequency is a cumulative effect of the non-uniform distribution of the high frequency current in the bolometer and the charge imbalance, which occurs near the edges of the normal domain and contacts with normal metal. In addition, we present experimental results which show that the noise temperature of a HEB mixer can be reduced by about 30% due to a Parylene antireflection coating on the Silicon hyperhemispheric lens.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor (down)  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
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  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 305  
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Author Semenov, A. D.; Hübers, H.-W.; Schubert, J.; Gol'tsman, G. N.; Elantiev, A. I.; Voronov, B. M.; Gershenzon, E. M. url  doi
openurl 
  Title Design and performance of the lattice-cooled hot-electron terahertz mixer Type Journal Article
  Year 2000 Publication J. Appl. Phys. Abbreviated Journal J. Appl. Phys.  
  Volume 88 Issue 11 Pages 6758-6767  
  Keywords HEB mixer, charge imbalance, HF current distribution  
  Abstract We present the measurements and the theoreticalmodel of the frequency-dependent noise temperature of a superconductor lattice-cooled hot-electron bolometer mixer in the terahertz frequency range. The increase of the noise temperature with frequency is a cumulative effect of the nonuniform distribution of the high-frequency current in the bolometer and the charge imbalance, which occurs at the edges of the normal domain and at the contacts with normal metal. We show that under optimal operation the fluctuation sensitivity of the mixer is determined by thermodynamic fluctuations of the noise power, whereas at small biases there appears additional noise, which is probably due to the flux flow. We propose the prescription of how to minimize the influence of the current distribution on the mixer performance.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor (down)  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0021-8979 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 306  
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Author Hübers, H.-W.; Semenov, A. D.; Richter, H.; Schubert, J.; Hadjiloucas, S.; Bowen, J. W.; Gol'tsman, G.; Voronov, B. M.; Gershenzon, E. M. url  openurl
  Title Antenna pattern of the quasi-optical hot-electron bolometric mixer at terahertz frequencies Type Conference Article
  Year 2001 Publication Proc. 12th Int. Symp. Space Terahertz Technol. Abbreviated Journal Proc. 12th Int. Symp. Space Terahertz Technol.  
  Volume Issue Pages 286-296  
  Keywords NbN HEB mixers  
  Abstract  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication San Diego, CA, USA Editor (down)  
  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 323  
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Author Il'in, K. S.; Lindgren, M.; Currie, M. A.; Semenov, D.; Gol'tsman, G. N.; Sobolewski, Roman; Cherednichenko, S. I.; Gershenzon, E. M. url  doi
openurl 
  Title Picosecond hot-electron energy relaxation in NbN superconducting photodetectors Type Journal Article
  Year 2000 Publication Appl. Phys. Lett. Abbreviated Journal Appl. Phys. Lett.  
  Volume 76 Issue 19 Pages 2752-2754  
  Keywords NbN HEB detectors, two-temperature model, IF bandwidth  
  Abstract We report time-resolved characterization of superconducting NbN hot-electron photodetectors using an electro-optic sampling method. Our samples were patterned into micron-size microbridges from 3.5-nm-thick NbN films deposited on sapphire substrates. The devices were illuminated with 100 fs optical pulses, and the photoresponse was measured in the ambient temperature range between 2.15 and 10.6 K (superconducting temperature transition TC). The experimental data agreed very well with the nonequilibrium hot-electron, two-temperature model. The quasiparticle thermalization time was ambient temperature independent and was measured to be 6.5 ps. The inelastic electron–phonon scattering time Ï„e–ph tended to decrease with the temperature increase, although its change remained within the experimental error, while the phonon escape time Ï„es decreased almost by a factor of two when the sample was put in direct contact with superfluid helium. Specifically, Ï„e–ph and Ï„es, fitted by the two-temperature model, were equal to 11.6 and 21 ps at 2.15 K, and 10(±2) and 38 ps at 10.5 K, respectively. The obtained value of Ï„e–ph shows that the maximum intermediate frequency bandwidth of NbN hot-electron phonon-cooled mixers operating at TC can reach 16(+4/–3) GHz if one eliminates the bolometric phonon-heating effect.  
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  Corporate Author Thesis  
  Publisher Place of Publication Editor (down)  
  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 856  
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Author Gershenzon, E. M.; Gol’tsman, G. N.; Gousev, Y. P.; Elant’ev, A. I.; Semenov, A. D. url  doi
openurl 
  Title Electromagnetic radiation mixer based on electron heating in resistive state of superconductive Nb and YBaCuO films Type Journal Article
  Year 1991 Publication IEEE Trans. Magn. Abbreviated Journal IEEE Trans. Magn.  
  Volume 27 Issue 2 Pages 1317-1320  
  Keywords YBCO, HTS, Nb HEB mixers  
  Abstract A theory of an electron-heating mixer which makes it possible to calculate all the characteristics of the device is developed. It is shown that positive conversion gain is possible for such a mixer in the millimeter to near-infrared wavelength range. The dynamic range and the optimum heterodyne power can be selected from a very wide interval by varying the mixing element volume. Measurements made for Nb within the frequency range of 120-750 GHz confirm the theory. The conversion loss obtained at T=1.6 K and normalized to the element reaches 0.3 dB in the intermediate frequency band of 40 MHz; the possible noise temperature is 50 K. The estimation of noise temperature and output band for YBaCuO at T=77 yields 200 K and more than 10 GHz, respectively.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor (down)  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1941-0069 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1681  
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