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Author Siddiqi, I.; Prober, D. E.
Title Nb–Au bilayer hot-electron bolometers for low-noise THz heterodyne detection Type Journal Article
Year 2004 Publication Applied Physics Letters Abbreviated Journal Appl. Phys. Lett.
Volume 84 Issue 8 Pages 1404
Keywords (up) HEB, mixers, dynamic range, saturation, LO power, local oscillator power, Nb
Abstract The sensitivity of present Nb diffusion-cooled hot-electron bolometer (HEB) mixers is not quantum limited, and can be improved by reducing the superconducting transition temperature TC. Lowering TC reduces thermal fluctuations, resulting in a decrease of the mixer noise temperature TM. However, lower TC mixers have reduced dynamic range and saturate more easily due to background noise. We present 30 GHz microwave measurements on a bilayer HEB system, Nb–Au, in which TC can be tuned with Au layer thickness to obtain the maximum sensitivity for a given noise background. These measurements are intended as a guide for the optimization of THz mixers. Using a Nb–Au mixer with TC = 1.6 K, we obtain TM = 50 K with 2 nW of local oscillator (LO) power. Good mixer performance is observed over a wide range of LO power and bias voltage and such a device should not exhibit saturation in a THz receiver.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-6951 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 571
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Author Baselmans, J. J. A.; Hajenius, M.; Gao, J.; de Korte, P.; Klapwijk, T. M.; Voronov, B.; Gol’tsman, G.
Title Doubling of sensitivity and bandwidth in phonon-cooled hot-electron bolometer mixers Type Conference Article
Year 2004 Publication Proc. SPIE Abbreviated Journal Proc. SPIE
Volume 5498 Issue Pages 168-176
Keywords (up) Hot electron bolometers, bandwidth, noise temperature, experimental
Abstract NbN hot electron bolometer (HEB) mixers are at this moment the best heterodyne detectors for frequencies above 1 THz. However, the fabrication procedure of these devices is such that the quality of the interface between the NbN superconducting film and the contact structure is not under good control. This results in a contact resistance between the NbN bolometer and the contact pad. We compare identical bolometers, with different NbN – contact pad interfaces, coupled with a spiral antenna. We find that cleaning the NbN interface and adding a thin additional superconductor prior to the gold contact deposition improves the noise temperature and the bandwidth of the HEB mixers with more than a factor of 2. We obtain a DSB noise temperature of 950 K at 2.5 THz and a Gain bandwidth of 5-6 GHz. For use in real receiver systems we design small volume (0.15x1 micron) HEB mixers with a twin slot antenna. We find that these mixers combine good sensitivity (900 K at 1.6 THz) with low LO power requirement, which is 160 – 240 nW at the Si lens of the mixer. This value is larger than expected from the isothermal technique and the known losses in the lens by a factor of 3-3.5.
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Publisher SPIE Place of Publication Editor Zmuidzinas, J.; Holland, W.S.; Withington, S.
Language Summary Language Original Title
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ISSN ISBN Medium
Area Expedition Conference Millimeter and Submillimeter Detectors for Astronomy II
Notes Approved no
Call Number Serial 1744
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Author Kaurova, N. S.; Finkel, M. I.; Maslennikov, S. N.; Vahtomin, Yu. B.; Antipov, S. V.; Smirnov, K. V.; Voronov, B. M.; Gol'tsman, G. N.; Ilyin, K. S.
Title Submillimeter mixer based on YBa2Cu3O7-x thin film Type Conference Article
Year 2004 Publication Proc. 1-st conf. Fundamental problems of high temperature superconductivity Abbreviated Journal
Volume Issue Pages 291
Keywords (up) HTS, HEB mixer
Abstract
Address Moscow-Zvenigorod
Corporate Author Thesis
Publisher Place of Publication Moscow-Zvenigorod Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
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Area Expedition Conference
Notes Approved no
Call Number Serial 355
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Author Klaassen, T. O.; Hovenier, J. N.; Adam, A. J. L.; Fischer, J.; Jakob, G.; Poglitsch, A.; Redlich, B.
Title Terahertz calorimetry for the Herschel Space Observatory Type Conference Article
Year 2004 Publication Proc. 29th IRMMW / 12th THz Abbreviated Journal
Volume Issue Pages 815-816
Keywords (up) mirror, reflection index, emissivity, calorimetry, space observatory, terahertz, THz
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Publisher Place of Publication Editor
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Notes Approved no
Call Number Serial 578
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Author van't Klooster, K.; Myasnikova, S. E.; Parshin, V. V.; Kasparek, W.
Title Results of reflection loss measurements of sample material for radio astronomy telescope antenna for Planck Project Type Conference Article
Year 2004 Publication Proc. 14th international crimean conference on microwave and telecommunication technology Abbreviated Journal
Volume Issue Pages 753-755
Keywords (up) mirror, reflection index, emissivity, Fabry-Perot interferometer, space observatory, terahertz, THz
Abstract Advanced radio telescope antennas for space applications are realised by the use of stable composite materials, which are lighter in general than various metal realisations. Reflectivity measurements have been carried out on high technology samples for the Planck radio telescope. Highly accurate results have been obtained at the Applied Physics Institute in Nizhny Novgorod, and an independent measurement with a totally different setup at the University of Stuttgart confirmed that one of the samples showed a strange behaviour. Moreover, it confirmed the high accuracy of the testing method.
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Area Expedition Conference
Notes Approved no
Call Number Serial 579
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