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Author Delsim-Yashemi, H.; Fröhlich, L.; Grimm, O.
Title Detector response and beam line transmission measurements with far-infrared radiation Type Conference Article
Year 2005 Publication Proc. 27th International free electron laser conference Abbreviated Journal
Volume Issue Pages (down) 106-109
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Corporate Author Thesis
Publisher Place of Publication Stanford, California Editor
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Area Expedition Conference
Notes Approved no
Call Number Serial 448
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Author Chulkova, G.; Milostnaya, I.; Korneev, A.; Minaeva, O.; Rubtsova, I.; Voronov, B.; Okunev, O.; Smirnov, K.; Gol’tsman, G.; Kitaygorsky, J.; Cross, A.; Pearlman, A.; Sobolewski, R.; Slysz, W.
Title Superconducting nanostructures for counting of single photons in the infrared range Type Conference Article
Year 2005 Publication Proc. 2-nd CAOL Abbreviated Journal Proc. 2-nd CAOL
Volume 2 Issue Pages (down) 100-103
Keywords SSPD, SNSPD
Abstract We present our studies on ultrafast superconducting single-photon detectors (SSPDs) based on ultrathin NbN nanostructures. Our SSPDs are patterned by electron beam lithography from 4-nm thick NbN film into meander-shaped strips covering square area of 10/spl times/10 /spl mu/m/sup 2/. The advances in the fabrication technology allowed us to produce highly uniform 100-120-nm-wide strips with meander filling factor close to 0.6. The detectors exploit a combined detection mechanism, where upon a single-photon absorption, an avalanche of excited hot electrons and the biasing supercurrent, jointly produce a picosecond voltage transient response across the superconducting nanostrip. The SSPDs are typically operated at 4.2 K, but they have shown that their sensitivity in the infrared radiation range can be significantly improved by lowering the operating temperature from 4.2 K to 2 K. When operated at 2 K, the SSPD quantum efficiency (QE) for visible light photons reaches 30-40%, which is the saturation value limited by optical absorption of our 4-nm-thick NbN film. For 1.55 /spl mu/m photons, QE was /spl sim/20% and decreases exponentially with the increase of the optical wavelength, but even at the wavelength of 6 /spl mu/m the detector remains sensitive to single photons and exhibits QE of about 10/sup -2/%. The dark (false) count rate at 2 K is as low as 2 /spl times/ 10/sup -4/ s/sup -1/, what makes our detector essentially a background-limited sensor. The very low dark-count rate results in the noise equivalent power (NEP) as low as 10/sup -18/ WHz/sup -1/2/ for the mid-infrared range (6 /spl mu/m). Further improvement of the SSPD performance in the mid-infrared range can be obtained by substituting NbN for the other, lower-T/sub c/ superconductors with the narrow superconducting gap and low quasiparticle diffusivity. The use of such materials will shift the cutoff wavelength towards the values even longer than 6 /spl mu/m.
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Area Expedition Conference Second International Conference on Advanced Optoelectronics and Lasers
Notes Approved no
Call Number Serial 1461
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Author Encrenaz, Thérèse
Title Neutral Atmospheres of the Giant Planets: An Overview of Composition Measurements Type Journal Article
Year 2005 Publication Space Science Reviews Abbreviated Journal Space Sci Rev
Volume 116 Issue 1-2 Pages (down) 99-119
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ISSN 0038-6308 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number RPLAB @ s @ Serial 443
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Author Gol'tsman, Gregory N.; Vachtomin, Yuriy B.; Antipov, Sergey V.; Finkel, Matvey I.; Maslennikov, Sergey N.; Smirnov, Konstantin V.; Polyakov, Stanislav L.; Svechnikov, Sergey I.; Kaurova, Natalia S.; Grishina, Elisaveta V.; Voronov, Boris M.
Title NbN phonon-cooled hot-electron bolometer mixer for terahertz heterodyne receivers Type Conference Article
Year 2005 Publication Proc. SPIE Abbreviated Journal Proc. SPIE
Volume 5727 Issue Pages (down) 95-106
Keywords NbN HEB mixers
Abstract We present the results of our studies of NbN phonon-cooled HEB mixers at terahertz frequencies. The mixers were fabricated from NbN film deposited on a high-resistivity Si substrate with an 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 x 0.2 μm2 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. The largest gain bandwidth of 5.2 GHz was achieved for a mixer based on 2 nm thick NbN film deposited on MgO layer over Si substrate. The gain bandwidth of the mixer based on 3.5 nm NbN film deposited on Si with MgO is 4.2 GHz and the noise bandwidth for the same device amounts to 5 GHz. We also present the results of our research into decrease of the direct detection contribution to the measured Y-factor and a possible error of noise temperature calculation. The use of a square nickel cell mesh as an IR-filter enabled us to avoid the effect of direct detection and measure apparent value of the noise temperature which was 16% less than that obtained using conventional black polyethylene IR-filter.
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Area Expedition Conference Terahertz and Gigahertz Electronics and Photonics IV
Notes Approved no
Call Number Serial 378
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Author Marrone, Daniel P.; Raymond Blundell; Edward Tong; Paine, Scott. N.; Denis Loudkov; Jonathan Kawamura; Daniel Luhr; Claudio Barrientos
Title Observations in the 1.3 and 1.5 THz atmospheric windows with the Receiver Lab Telescope Type Conference Article
Year 2005 Publication Proc. 16th Int. Symp. Space Terahertz Technol. Abbreviated Journal
Volume Issue Pages (down) 64-67
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Corporate Author Thesis
Publisher Place of Publication Göteborg, Sweden Editor
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Area Expedition Conference
Notes Approved no
Call Number RPLAB @ s @ RLT_observ Serial 361
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