Records |
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Semenov, A. D.; Hübers, H.-W.; Richter, H.; Birk, M.; Krocka, M.; Mair, U.; Smirnov, K.; Gol'tsman, G. N.; Voronov, B. M. |
Title |
2.5 THz heterodyne receiver with NbN hot-electron-bolometer mixer |
Type |
Journal Article |
Year |
2002 |
Publication |
Phys. C: Supercond. |
Abbreviated Journal |
Phys. C: Supercond. |
Volume |
372-376 |
Issue |
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Pages |
448-453 |
Keywords |
NbN HEB mixers, applications |
Abstract |
We describe a 2.5 THz heterodyne receiver for applications in astronomy and atmospheric research. The receiver employs a superconducting NbN phonon-cooled hot-electron-bolometer mixer and an optically pumped far-infrared gas laser as local oscillator. 2200 K double sideband mixer noise temperature was measured at 2.5 THz across a 1 GHz intermediate frequency bandwidth centred at 1.5 GHz. The total conversion losses were 17 dB. The mixer response was linear at load temperatures smaller than 400 K. The receiver was tested in the laboratory environment by measuring the methanol line in emission. Observed pressure broadening confirms the true heterodyne detection regime of the mixer. |
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0921-4534 |
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1526 |
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Author ![sorted by Author field, ascending order (up)](img/sort_asc.gif) |
Semenov, A. D.; Sergeev, A. V.; Kouminov, P.; Goghidze, I. G.; Heusinger, M. A.; Nebosis, R. S.; Gol'tsman, G. N.; Gershenzon, E. M.; Renk, K. F. |
Title |
Transparency of YBCO film/substrate interfaces for thermal phonons determined by photoresponse measurements |
Type |
Conference Article |
Year |
1993 |
Publication |
Proc. 1st European Conf. on Appl. Supercond. |
Abbreviated Journal |
Proc. 1st European Conf. on Appl. Supercond. |
Volume |
2 |
Issue |
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Pages |
1443-1446 |
Keywords |
YBCO HTS detectors |
Abstract |
Direct measurements of the thermal boundary resistance were performed by means of the stationary method. In this approach the temperature of an electrically heated film is controlled by its dc resistance while an additional film on the same substrate is used as a thermometer monitoring substrate temperature. The temperature field in the substrate is then calculated to deduce the Kapitza temperature step at the interface between the heated strip and the substrate. The main statement of all afore-said papers is that experimental values of the thermal boundary resistance are too large to be explained by the acoustic mismatch model. In this paper we investigate transparency of YBaCuO film/substrate interfaces for thermal phonons by means of photoresponse measurements. We show that our data are in reasonable agreement with the acoustic mismatch theory. |
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Freyhardt, H. C. |
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3-88355-197-X |
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1st European conference on applied superconductivity |
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1661 |
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Semenov, A. V.; Devyatov, I. A.; Korneev, A. A.; Smirnov, K. V.; Goltsman, G. N.; Melnikov, A. P. |
Title |
Derivation of expression for thermodynamic potential of “dirty” superconductor |
Type |
Journal Article |
Year |
2012 |
Publication |
Rus. J. Radio Electron. |
Abbreviated Journal |
Rus. J. Radio Electron. |
Volume |
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Issue |
4 |
Pages |
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Keywords |
dirty superconductor, Usadel theory, thermodynamic potential |
Abstract |
We derive a formula for thermodynamic potential of dirty superconductor which express it via isotropic quasiclassical Green functions of Usadel theory. Our result allows unify description of dynamic processes and fluctuations in superconducting nano-electronic devices. |
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Russian |
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7 pages |
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1824 |
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Semenov, A.; Hübers, H.-W.; Engel, A.; Gol’tsman, G. |
Title |
Superconducting quantum detector for far infrared astronomy |
Type |
Conference Article |
Year |
2002 |
Publication |
Far-IR, Sub-mm & MM Detector Technology Workshop |
Abbreviated Journal |
Far-IR, Sub-mm & MM Detector Technology Workshop |
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Pages |
3-49 |
Keywords |
SQD |
Abstract |
We present the concept of the superconducting quantum detector for astronomy. Response to a single absorbed photon appears due to successive formation of a normal spot and phase-slip-centres in a narrow strip carrying sub-critical supercurrent. The detector simultaneously has a moderate energy resolution and a variable cut-off wavelength depending on both the material used and operation conditions. We simulated performance of the background-limited direct detector having the 100-micrometer cut-off wavelength. Low dark count rate will allow to realise 10-21 W Hz-1/2 noise equivalent power at 4 K background radiation. The detection mechanism provides a moderate 1/20 energy resolution at 50-micrometer wavelength. |
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NASA |
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Wolf, J.; Farhoomand, J.; McCreight, C.R. |
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NASA CP |
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Notes |
Volume: 211408 |
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no |
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1538 |
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Semenov, A.; Richter, H.; Hübers, H.-W.; Petrenko, D.; Tretyakov, I.; Ryabchun, S.; Finkel, M.; Kaurova, N.; Gol’tsman, G.; Risacher, C.; Ricken, O.; Güsten, R. |
Title |
Optimization of the intermediate frequency bandwidth in the THz HEB mixers |
Type |
Abstract |
Year |
2014 |
Publication |
Proc. 25th Int. Symp. Space Terahertz Technol. |
Abbreviated Journal |
Proc. 25th Int. Symp. Space Terahertz Technol. |
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Pages |
54 |
Keywords |
NbN HEB mixer |
Abstract |
We report on the studies of the intermediate frequency (IF) bandwidth of quasi-optically coupled NbN hot-electron bolometer (HEB) mixers which are aimed at the optimization of the mixer performance at terahertz frequencies. Extension of the IF bandwidth due to the contribution of electron diffusion to the heat removal from NbN microbolometers has been already demonstrated for NbN HEBs at subterahertz frequencies. However, reducing the size of the microbolometer causes degradation of the noise temperature. Using in-situ multilayer manufacturing process we succeeded to improve the transparency of the contacts for electrons which go away from microbolometer to the metallic antenna. The improved transparency and hence coupling efficiency counterbalances the noise temperature degradation. HEB mixers were tested in a laboratory heterodyne receiver with a narrow-band cold filter which allowed us to eliminate direct detection. We used a local oscillator with a quantum cascade laser (QCL) at a frequency of 4.745 THz [1] which was developed for the H-Channel of the German Receiver for Astronomy at Terahertz frequencies (GREAT). Both the noise and gain bandwidth were measured in the IF range from 0.5 to 8 GHz using the hot-cold technique and preliminary calibrated IF analyzer with a tunable microwave filter. For optimized HEB geometry we found the noise bandwidth as large as 7 GHz. We compare our results with the conventional and the hot-spot mixer models and show that further extension of the IF bandwidth should be possible via improving the sharpness of the superconducting transition. The cross characterization of the HEB mixer was performed in the test bed of GREAT at the Max-Planck-Institut für Radioastronomie with the same QCL LO and delivered results which were consistent with the laboratory studies. |
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1359 |
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