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Author Kawamura, J.; Tong, C.-Y. E.; Blundell, R.; Papa, D. C.; Hunter, T. R.; Patt, F.; Gol’tsman, G.; Gershenzon, E. url  doi
openurl 
  Title Terahertz-frequency waveguide NbN hot-electron bolometer mixer Type Journal Article
  Year 2001 Publication IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.  
  Volume (down) 11 Issue 1 Pages 952-954  
  Keywords NbN HEB mixers  
  Abstract We have developed a low-noise waveguide heterodyne receiver for operation near 1 THz using phonon-cooled NbN hot-electron bolometers. The mixer elements are submicron-sized microbridges of 4 nm-thick NbN film fabricated on a quartz substrate. Operating at a bath temperature of 4.2 K, the double-sideband receiver noise temperature is 760 K at 1.02 THz and 1100 K at 1.26 THz. The local oscillator is provided by solid-state sources, and power measured at the source is less than 1 /spl mu/W. The intermediate frequency bandwidth exceeds 2 GHz. The receiver was used to make the first ground-based heterodyne detection of a celestial spectroscopic line above 1 THz.  
  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 1558-2515 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1546  
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Author Kawamura, J. H.; Tong, C.-Y.E.; Blundell, R.; Cosmo Papa, D.; Hunter, T. R.; Gol'tsman, G.; Cherednichenko, S.; Voronov, B.; Gershenzon, E. url  doi
openurl 
  Title An 800 GHz NbN phonon-cooled hot-electron bolometer mixer receiver Type Journal Article
  Year 1999 Publication IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.  
  Volume (down) 9 Issue 2 Pages 3753-3756  
  Keywords NbN HEB mixers  
  Abstract We describe a heterodyne receiver developed for astronomical applications to operate in the 350 /spl mu/m atmospheric window. The waveguide receiver employs a superconductive NbN phonon-cooled hot-electron bolometer mixer. The double sideband receiver noise temperature closely follows 1 kGHz/sup -1/ across 780-870 GHz, with the intermediate frequency centered at 1.4 GHz. The conversion loss is about 15 dB. The receiver was installed for operation at the University of Arizona/Max Planck Institute for Radio Astronomy Submillimeter Telescope facility. The instrument was successfully used to conduct test observations of a number of celestial sources in a number of astronomically important spectral lines.  
  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 1051-8223 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 288  
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Author Schwaab, G.W.; Sirmain, G.; Schubert, J.; Hubers, H.-W.; Gol'tsman, G.; Cherednichenko, S.; Verevkin, A.; Voronov, B.; Gershenzon, E. url  doi
openurl 
  Title Investigation of NbN phonon-cooled HEB mixers at 2.5 THz Type Journal Article
  Year 1999 Publication IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.  
  Volume (down) 9 Issue 2 Pages 4233-4236  
  Keywords NbN HEB mixers  
  Abstract The development of superconducting hot electron bolometric (HEB) mixers has been a big step forward in the direction of quantum noise limited mixer performance at THz frequencies. Such mixers are crucial for the upcoming generation of airborne and spaceborne THz heterodyne receivers. In this paper we report on new results on a phonon-cooled NbN HEB mixer using e-beam lithography. The superconducting film is 3 nm thick. The mixer is 0.2 μm long and 1.5 μm wide and it is integrated in a spiral antenna on a Si substrate. The device is quasi-optically coupled through a Si lens and a dielectric beam combiner to the radiation of an optically pumped FIR ring gas laser cavity. The performance of the mixer at different THz frequencies from 0.69 to 2.55 THz with an emphasis on 2.52 THz is demonstrated. At 2.52 THz minimum DSB noise temperatures of 4200 K have been achieved at an IF of 1.5 GHz and a bandwidth of 40 MHz with the mixer mounted in a cryostat and a 0.8 m long signal path in air.  
  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 1051-8223 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 550  
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Author Il'in, K. S.; Currie, M.; Lindgren, M.; Milostnaya, I. I.; Verevkin, A. A.; Gol'tsman, G. N.; Sobolewski, R. url  doi
openurl 
  Title Quantum efficiency and time-domain response of superconducting NbN hot-electron photodetectors Type Journal Article
  Year 1999 Publication IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.  
  Volume (down) 9 Issue 2 Pages 3338-3341  
  Keywords NbN SSPD, SNSPD  
  Abstract We report our studies on the response of ultrathin superconducting NbN hot-electron photodetectors. We have measured the photoresponse of few-nm-thick, micron-size structures, which consisted of single and multiple microbridges, to radiation from the continuous-wave semiconductor laser and the femtosecond Ti:sapphire laser with the wavelength of 790 nm and 400 nm, respectively. The maximum responsivity was observed near the film's superconducting transition with the device optimally current-biased in the resistive state. The responsivity of the detector, normalized to its illuminated area and the coupling factor, was 220 A/W(3/spl times/10/sup 4/ V/W), which corresponded to a quantum efficiency of 340. The responsivity was wavelength independent from the far infrared to the ultraviolet range, and was at least two orders of magnitude higher than comparable semiconductor optical detectors. The time constant of the photoresponse signal was 45 ps, when was measured at 2.15 K in the resistive (switched) state using a cryogenic electro-optical sampling technique with subpicosecond resolution. The obtained results agree very well with our calculations performed using a two-temperature model of the electron heating in thin superconducting films.  
  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 1051-8223 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1566  
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Author Semenov, A. D.; Gol'tsman, G. N. url  doi
openurl 
  Title Non-thermal response of a diffusion-cooled hot-electron bolometer Type Journal Article
  Year 1999 Publication IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.  
  Volume (down) 9 Issue 2 Pages 4491-4494  
  Keywords HEB mixers, non-thermal  
  Abstract We present an analysis of a diffusion-cooled hot-electron bolometer in the limiting case of a weak thermalization of non-equilibrium quasiparticles. We propose a new model relying on the non-thermal suppression of the superconducting energy gap by excess quasiparticles. Using material parameters typical for Al, we evaluate performance of the bolometer in the heterodyne regime at terahertz frequencies. Estimates show that the mixer may have quantum limited noise temperature and a few tens of GHz bandwidth, while the required local oscillator power is in the /spl mu/W range due to in-effective suppression of the energy gap by quasiparticles with high energies.  
  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 1051-8223 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1567  
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