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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.
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.
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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.
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.
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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.
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
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Corporate Author Thesis
Publisher Place of Publication San Diego, CA, USA Editor
Language Summary Language Original Title
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Notes Approved no
Call Number Serial 323
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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 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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Notes Approved no
Call Number Serial 343
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Author Vachtomin, Y. B.; Antipov, S. V.; Maslennikov, S. N.; Smirnov, K. V.; Polyakov, S. L.; Kaurova, N. S.; Grishina, E. V.; Voronov, B. M.; Gol'tsman, G. N.
Title Noise temperature measurements of NbN phonon-cooled hot electron bolometer mixer at 2.5 and 3.8 THz Type Conference Article
Year 2004 Publication Proc. 15th Int. Symp. Space Terahertz Technol. Abbreviated Journal Proc. 15th Int. Symp. Space Terahertz Technol.
Volume Issue Pages 236-241
Keywords HEB mixer, NbN, direct detection effect
Abstract We present the results of noise temperature measurements of NbN phonon-cooled HEB mixers based on a 3.5 nm NbN film deposited on a high-resistivity Si substrate with a 200 nm – thick MgO buffer layer. The mixer element was integrated with a log-periodic spiral antenna. The noise temperature measurements were performed at 2.5 THz and at 3.8 THz local oscillator frequencies for the 3 µm x 0.2 µm active area devices. The best uncorrected receiver noise temperatures found for these frequencies are 1300 K and 3100 K, respectively. A water vapour discharge laser was used as the LO source. We also present the results of direct detection contribution to the measured Y-factor and of a possible error of noise temperature calculation. This error was more than 8% for the mixer with in-plane dimensions of 2.4 x 0.16 µm 2 at the optimal noise temperature point. The use of a mesh filter enabled us to avoid the effect of direct detection and decrease optical losses by 0.5 dB. The paper is concluded by the investigation results of the mixer polarization response. It was shown that the polarization can differ from the circular one at 3.8 THz by more than 2 dB.
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Corporate Author Thesis
Publisher Place of Publication Northampton, Massachusetts, USA Editor
Language Summary Language Original Title
Series Editor Series Title (up) Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 344
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