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Author Semenov, A. D.; Hübers, Heinz-Wilhelm; Richter, H.; Birk, M.; Krocka, M.; Mair, U.; Vachtomin, Yu. B.; Finkel, M. I.; Antipov, S. V.; Voronov, B. M.; Smirnov, K. V.; Kaurova, N. S.; Drakinski, V. N.; Gol'tsman, G. N.
Title Superconducting hot-electron bolometer mixer for terahertz heterodyne receivers Type Journal Article
Year 2003 Publication (up) IEEE Trans. Appl. Supercond. Abbreviated Journal
Volume 13 Issue 2 Pages 168-171
Keywords NbN HEB mixers
Abstract We present recent results showing the development of superconducting NbN hot-electron bolometer mixer for German receiver for astronomy at terahertz frequencies and terahertz limb sounder. The mixer is incorporated into a planar feed antenna, which has either logarithmic spiral or double-slot configuration, and backed on a silicon lens. The hybrid antenna had almost frequency independent and symmetric radiation pattern slightly broader than expected for a diffraction limited antenna. At 2.5 THz the best 2200 K double side-band receiver noise temperature was achieved across a 1 GHz intermediate frequency bandwidth centred at 1.5 GHz. For this operation regime, a receiver conversion efficiency of -17 dB was directly measured and the loss budget was evaluated. The mixer response was linear at load temperatures smaller than 400 K. Implementation of the MgO buffer layer on Si resulted in an increased 5.2 GHz gain bandwidth. The receiver was tested in the laboratory environment by measuring a methanol emission line at 2.5 THz.
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Call Number Serial 343
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Author Semenov, A. D.; Gol'tsman, G. N.
Title Non-thermal response of a diffusion-cooled hot-electron bolometer Type Journal Article
Year 1999 Publication (up) IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.
Volume 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.
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ISSN 1051-8223 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1567
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Author Gousev, Y. P.; Semenov, A. D.; Goghidze, I. G.; Pechen, E. V.; Varlashkin, A. V.; Gol'tsman, G. N.; Gershenzon, E. M.; Renk, K. F.
Title Current dependent noise in a YBa2Cu3O7-δ hot-electron bolometer Type Journal Article
Year 1997 Publication (up) IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.
Volume 7 Issue 2 Pages 3556-3559
Keywords YBCO HTS HEB mixers
Abstract We investigated the output noise of a YBa2Cu3O7-δ (YBCO) superconducting hot-electron bolometer (HEB) in a large frequency range (10 kHz to 8 GHz); the bolometer either consisted of a structured 50 nm thick YBCO film on LaAlO/sub 3/ or a 30 nm thick film on a MgO substrate. We found that flicker noise dominated at low frequencies (below 1 MHz), while at higher frequencies Johnson noise and a current dependent noise were the main noise sources.
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ISSN 1051-8223 ISBN Medium
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Notes Approved no
Call Number Serial 1592
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Author Semenov, A. D.; Gousev, Y. P.; Renk, K. F.; Voronov, B. M.; Gol'tsman, G. N.; Gershenzon, E. M.; Schwaab, G.W.; Feinaugle, R.
Title Noise characteristics of a NbN hot-electron mixer at 2.5 THz Type Journal Article
Year 1997 Publication (up) IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.
Volume 7 Issue 2 Pages 3572-3575
Keywords NbN HEB mixers
Abstract The noise temperature of a NbN phonon cooled hot-electron mixer has been measured at a frequency of 2.5 THz for various operating conditions. We obtained for optimal operation a double sideband mixer noise temperature of /spl ap/14000 K and a system conversion loss of /spl ap/23 dB at intermediate frequencies up to 1 GHz. The dependences of the mixer noise temperature on the bias voltage, local oscillator power, and intermediate frequency were consistent with the phenomenological description based on the effective temperature approximation.
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ISSN 1051-8223 ISBN Medium
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Notes Approved no
Call Number Serial 1594
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Author Semenov, A. D.; Heusinger, M. A.; Renk, K. F.; Menschikov, E.; Sergeev, A. V.; Elant'ev, A. I.; Goghidze, I. G.; Gol'tsman, G. N.
Title Influence of phonon trapping on the performance of NbN kinetic inductance detectors Type Journal Article
Year 1997 Publication (up) IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.
Volume 7 Issue 2 Pages 3083-3086
Keywords NbN KID
Abstract Voltage and microwave photoresponse of NbN thin films to modulated and pulsed optical radiation reveals, far below the superconducting transition, a response time consistent with the lifetime of nonequilibrium quasiparticles. We show that even in 5 nm thick films at 4.2 K the phonon trapping is significant resulting in a quasiparticle lifetime of a few nanoseconds that is an order of magnitude larger than the recombination time. Values and temperature dependence of the quasiparticle lifetime obey the Bardeen-Cooper-Schrieffer theory and are in quantitative agreement with the electron-phonon relaxation rate determined from the resistive response near the superconducting transition. We discuss a positive effect of the phonon trapping on the performance of kinetic inductance detectors.
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ISSN 1051-8223 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1598
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