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Author Kawamura, J.; Tong, C.-Y. E.; Blundell, R.; Papa, D. C.; Hunter, T. R.; Patt, F.; Gol’tsman, G.; Gershenzon, E.
Title Terahertz-frequency waveguide NbN hot-electron bolometer mixer Type Journal Article
Year 2001 Publication IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.
Volume 11 Issue 1 Pages 952-954
Keywords NbN HEB mixers
Abstract We have developed a low-noise waveguide heterodyne receiver for operation near 1 THz using phonon-cooled NbN hot-electron bolometers. The mixer elements are submicron-sized microbridges of 4 nm-thick NbN film fabricated on a quartz substrate. Operating at a bath temperature of 4.2 K, the double-sideband receiver noise temperature is 760 K at 1.02 THz and 1100 K at 1.26 THz. The local oscillator is provided by solid-state sources, and power measured at the source is less than 1 /spl mu/W. The intermediate frequency bandwidth exceeds 2 GHz. The receiver was used to make the first ground-based heterodyne detection of a celestial spectroscopic line above 1 THz.
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Series Volume Series Issue Edition
ISSN (down) 1558-2515 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1546
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Author Tong, C.-Y.E.; Meledin, D.V.; Marrone, D.P.; Paine, S.N.; Gibson, H.; Blundell, R.
Title Near field vector beam measurements at 1 THz Type Journal Article
Year 2003 Publication IEEE Microw. Compon. Lett. Abbreviated Journal
Volume 13 Issue 6 Pages 235-237
Keywords HEB, mixer, waveguide, LO power, local oscillator power, saturation effect, dynamic range
Abstract We have performed near-field vector beam measurements at 1.03 THz to characterize and align the receiver optics of a superconducting receiver. The signal source is a harmonic generator mounted on an X-Y translation stage. We model the measured two-dimensional complex beam pattern by a fundamental Gaussian mode, from which we derive the position of the beam center, the beam radius and the direction of propagation. By performing scans in the planes separated by 400 mm, we have confirmed that our beam pattern measurements are highly reliable.
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Series Editor Series Title Abbreviated Series Title
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ISSN (down) 1531-1309 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number RPLAB @ lobanovyury @ Serial 574
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Author Meledin, D.; Tong, C.-Y. E.; Blundell, R.; Goltsman, G.
Title Measurement of intermediate frequency bandwidth of hot electron bolometer mixers at terahertz frequency range Type Journal Article
Year 2003 Publication IEEE Microw. Wireless Compon. Lett. Abbreviated Journal IEEE Microw. Wireless Compon. Lett.
Volume 13 Issue 11 Pages 493-495
Keywords waveguide NbN HEB mixers
Abstract We have developed a new experimental setup for measuring the IF bandwidth of superconducting hot electron bolometer mixers. In our measurement system we use a chopped hot filament as a broadband signal source, and can perform a high-speed IF scan with no loss of accuracy when compared to coherent methods. Using this technique we have measured the 3 dB IF bandwidth of hot electron bolometer mixers, designed for THz frequency operation, and made from 3-4 nm thick NbN film deposited on an MgO buffer layer over crystalline quartz.
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Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (down) 1531-1309 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1509
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Author Hübers, H.-W.; Schubert, J.; Krabbe, A.; Birk, M.; Wagner, G.; Semenov, A.; Gol’tsman, G.; Voronov, B.; Gershenzon, E.
Title Parylene anti-reflection coating of a quasi-optical hot-electron-bolometric mixer at terahertz frequencies Type Journal Article
Year 2001 Publication Infrared Physics & Technology Abbreviated Journal Infrared Physics & Technology
Volume 42 Issue 1 Pages 41-47
Keywords NbN HEB mixers, anti-reflection coating
Abstract Parylene C was investigated as anti-reflection coating for silicon at terahertz frequencies. Measurements with a Fourier-transform spectrometer show that the transmittance of pure silicon can be improved by about 30% when applying a layer of Parylene C with a quarter wavelength optical thickness. The 10% bandwidth of this coating extends from 1.5 to 3 THz for a center frequency of 2.3–2.5 THz, where the transmittance is constant. Heterodyne measurements demonstrate that the noise temperature of a hot-electron-bolometric mixer can be reduced significantly by coating the silicon lens of the hybrid antenna with a quarter wavelength Parylene C layer. Compared to the same mixer with an uncoated lens the improvement is about 30% at a frequency of 2.5 THz.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (down) 1350-4495 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1548
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Author Semenov, A.; Engel, A.; Il'in, K.; Gol'tsman, G.; Siegel, M.; Hübers, H.-W.
Title Ultimate performance of a superconducting quantum detector Type Journal Article
Year 2003 Publication Eur. Phys. J. Appl. Phys. Abbreviated Journal Eur. Phys. J. Appl. Phys.
Volume 21 Issue 3 Pages 171-178
Keywords NbN SSPD, SNSPD
Abstract We analyze the ultimate performance of a superconducting quantum detector in order to meet requirements for applications in near-infrared astronomy and X-ray spectroscopy. The detector exploits a combined detection mechanism, in which avalanche quasiparticle multiplication and the supercurrent jointly produce a voltage response to a single absorbed photon via successive formation of a photon-induced and a current-induced normal hotspot in a narrow superconducting strip. The response time of the detector should increase with the photon energy providing energy resolution. Depending on the superconducting material and operation conditions, the cut-off wavelength for the single-photon detection regime varies from infrared waves to visible light. We simulated the performance of the background-limited infrared direct detector and X-ray photon counter utilizing the above mechanism. Low dark count rate and intrinsic low-frequency cut-off allow for realizing a background limited noise equivalent power of 10−20 W Hz−1/2 for a far-infrared direct detector exposed to 4-K background radiation. At low temperatures, the intrinsic response time of the counter is rather determined by diffusion of nonequilibrium electrons than by the rate of energy transfer to phonons. Therefore, thermal fluctuations do not hamper energy resolution of the X-ray photon counter that should be better than 10−3 for 6-keV photons. Comparison of new data obtained with a Nb based detector and previously reported results on NbN quantum detectors support our estimates of ultimate detector performance.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (down) 1286-0042 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 534
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