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Zhang, W.; Li, N.; Jiang, L.; Ren, Y.; Yao, Q.-J.; Lin, Z.-H.; Shi, S.-C.; Voronov, B. M.; Gol’tsman, G. N. |
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Title |
Dependence of noise temperature of quasi-optical superconducting hot-electron bolometer mixers on bath temperature and optical-axis displacement |
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Conference Article |
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2008 |
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Proc. SPIE |
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Proc. SPIE |
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6840 |
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684007 (1 to 8) |
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Keywords |
NbN HEB mixers, noise temperature, LO power |
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Abstract  |
It is known that the increase of bath temperature results in the decrease of critical current of superconducting hot-electron bolometer (HEB) mixers owing to the depression of superconductivity, thus leading to the degradation of the mixer’s sensitivity. Here we report our study on the effect of bath temperature on the heterodyne mixing performance of quasi-optical superconducting NbN HEB mixers incorporated with a two-arm log-spiral antenna. The correlation between the bath temperature, critical current, LO power requirement and noise temperature is investigated at 0.5 THz. Furthermore, the heterodyne mixing performance of quasi-optical superconducting NbN HEB mixers is examined while there is an optical-axis displacement between the center of the extended hemispherical silicon lens and the superconducting NbN HEB device, which is placed on the back of the lens. Detailed experimental results and analysis are presented. |
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Spie |
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Zhang, C.; Zhang, X.-C. |
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Terahertz Photonics |
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1415 |
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Kawamura, J.; Blundell, R.; Tong, C.-yu E.; Gol’tsman, G.; Gershenzon, E.; Voronov, B.; Cherednichenko, S. |
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Title |
Low noise NbN lattice-cooled superconducting hot-electron bolometric mixers at submillimeter wavelengths |
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Journal Article |
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Year |
1997 |
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Appl. Phys. Lett. |
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Appl. Phys. Lett. |
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70 |
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12 |
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1619-1621 |
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Keywords |
NbN HEB mixers |
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Abstract |
Lattice-cooled superconducting hot-electron bolometric mixers are used in a submillimeter-wave waveguide heterodyne receiver. The mixer elements are niobium nitride film with 3.5 nm thickness and ∼10 μm2 area. The local oscillator power for optimal performance is estimated to be 0.5 μW, and the instantaneous bandwidth is 2.2 GHz. At an intermediate frequency centered at 1.4 GHz with 200 MHz bandwidth, the double sideband receiver noise temperature is 410 K at 430 GHz. The receiver has been used to detect molecular line emission in a laboratory gas cell. |
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0003-6951 |
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1599 |
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Engel, Andreas; Aeschbacher, Adrian; Inderbitzin, Kevin; Schilling, Andreas; Il'in, Konstantin; Hofherr, Matthias; Siegel, Michael; Semenov, Alexei; Hübers, Heinz-Wilhelm |
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Title |
Tantalum nitride superconducting single-photon detectors with low cut-off energy |
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2011 |
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arXiv |
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arXiv |
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9 |
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SSPD |
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Materials with a small superconducting energy gap favor a high detection efficiency of low-energy photons in superconducting nanowire single-photon detectors. We developed a TaN detector with smaller gap and lower density of states at the Fermi energy than in comparable NbN devices, while other relevant parameters remain essentially unchanged. This results in a reduction of the minimum photon energy required for direct detection to $\approx1/3$ as compared to NbN. |
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arXiv:1110.4576 |
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RPLAB @ gujma @ |
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687 |
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Wild, W.; Kardashev, N. S.; Likhachev, S. F.; Babakin, N. G.; Arkhipov, V. Y.; Vinogradov, I. S.; Andreyanov, V. V.; Fedorchuk, S. D.; Myshonkova, N. V.; Alexsandrov, Y. A.; Novokov, I. D.; Goltsman, G. N.; Cherepaschuk, A. M.; Shustov, B. M.; Vystavkin, A. N.; Koshelets, V. P.; Vdovin, V.F.; de Graauw, T.; Helmich, F.; vd Tak, F.; Shipman, R.; Baryshev, A.; Gao, J. R.; Khosropanah, P.; Roelfsema, P.; Barthel, P.; Spaans, M.; Mendez, M.; Klapwijk, T.; Israel, F.; Hogerheijde, M.; vd Werf, P.; Cernicharo, J.; Martin-Pintado, J.; Planesas, P.; Gallego, J. D.; Beaudin, G.; Krieg, J. M.; Gerin, M.; Pagani, L.; Saraceno, P.; Di Giorgio, A. M.; Cerulli, R.; Orfei, R.; Spinoglio, L.; Piazzo, L.; Liseau, R.; Belitsky, V.; Cherednichenko, S.; Poglitsch, A.; Raab, W.; Guesten, R.; Klein, B.; Stutzki, J.; Honingh, N.; Benz, A.; Murphy, A.; Trappe, N.; Räisänen, A. |
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Title |
Millimetron—a large Russian-European submillimeter space observatory |
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Journal Article |
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2009 |
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Exp. Astron. |
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Exp. Astron. |
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23 |
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1 |
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221-244 |
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Millimetron space observatory, VLBI, very long baseline interferometry |
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Millimetron is a Russian-led 12 m diameter submillimeter and far-infrared space observatory which is included in the Space Plan of the Russian Federation for launch around 2017. With its large collecting area and state-of-the-art receivers, it will enable unique science and allow at least one order of magnitude improvement with respect to the Herschel Space Observatory. Millimetron will be operated in two basic observing modes: as a single-dish observatory, and as an element of a ground-space very long baseline interferometry (VLBI) system. As single-dish, angular resolutions on the order of 3 to 12 arc sec will be achieved and spectral resolutions of up to a million employing heterodyne techniques. As VLBI antenna, the chosen elliptical orbit will provide extremely large VLBI baselines (beyond 300,000 km) resulting in micro-arc second angular resolution. |
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0922-6435 |
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1402 |
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Author |
Darula, Marian; Semenov, Alex D.; Hübers, Heinz-Wilhelm; Schubert, Josef |
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Title |
Quasioptical high-Tc superconductor Josephson mixer at terahertz frequencies |
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Abstract |
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2000 |
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Proc. 11th Int. Symp. Space Terahertz Technol. |
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Proc. 11th Int. Symp. Space Terahertz Technol. |
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515 |
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HTS Josephson mixers |
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Mixers based on Josephson junctions from conventional superconductor materials have demonstrated excellent performance at subgap frequencies. The advantages of Josephson mixers are low optimal power of the local oscillator and large intermediate frequency bandwidth but their noise temperature increases dramatically at frequencies corresponding to the energy gap of the superconductor, which is typically below 1 THz for widely used materials. The large energy gap of oxide superconductors makes them promising candidates for development of terahertz Josephson mixers. Here we report on experimental study of the quasioptical mixer utilizing bicrystal Josephson junction from high-transition-temperature YBa 2 Cu 3 O 7-δ film. Junctions with a width of 2 µm were fabricated from 100 nm thick laser ablated films on bicrystal MgO substrates and had the and the J C R n product of about 2 mV at 4.2 K. The planar complementary logarithmic spiral antenna incorporated into co-planar waveguide was patterned from 200 nm thick gold film thermally evaporated in situ on top of the YBa 2 Cu 3 O 7-δ film. The mixer chip was clamped to the extended hemispherical silicon lens. Performance of the mixer was investigated at 4.5 K bath temperature. We used FIR laser as a local oscillator at frequencies 0.698 and 2.52 THz. System noise temperature (DSB) was determined from Y-factor measured with 300 K and 77 K loads. At 0.698 THz the lowest noise temperature 1750 K was observed when the mixer was biased with the fixed current to the region in the vicinity of either the first Shapiro step or the critical current. Between these two bias points the noise temperature increased to ≈ 20000 K. As function of the local oscillator power the noise temperature reached the minimum when the critical current was suppressed to the half of its equilibrium value. Power of the local oscillator absorbed by the mixer at optimal operation was of the order 100 nW. The present design of our antenna limits the upper operation frequency to the value of 1.8 THz. Nevertheless, we clearly observed Shapiro steps at the frequency 2.52 THz. Bearing in mind an improved design of the antenna, we estimate the 3000 K DSB noise temperature at this frequency. |
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1555 |
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