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Hübers, H. - W., Semenov, A., Richter, H., Birk, M., Krocka, M., Mair, U., et al. (2002). Terahertz Heterodyn Receiver with a hot-electron bolometer mixer. In U. Wolf, J. Farhoomand, & C. R. McCreight (Eds.), Far-IR, Sub-mm & MM Detector Technology Workshop (pp. 3–24). NASA CP. NASA.
Abstract: During the past decade major advances have been made regarding low noise mixers for terahertz (THz) heterodyne receivers. State of the art hot-electron-bolometer (HEB) mixers have noise temperatures close to the quantum limit and require less than a µW power from the local oscillator (LO). The technology is now at a point where the performance of a practical receiver employing such mixer, rather than the figures of merit of the mixer itself, are of major concern. We have incorporated a phonon-cooled NbN HEB mixer in a 2.5 THz heterodyne receiver and investigated the performance of the receiver. This yields important information for the development of heterodyne receivers such as GREAT (German receiver for astronomy at THz frequencies aboard SOFIA) [1] and TELIS (Terahertz limb sounder), a balloon borne heterodyne receiver for atmospheric research [2]. Both are currently under development at DLR.
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Hübers, H. - W., Semenov, A., Richter, H., Birk, M., Krocka, M., Mair, U., et al. (2002). Terahertz heterodyne receiver with a hot-electron bolometer mixer. In J. Wold, & J. Davidson (Eds.), Proc. Far-IR, Sub-mm, and mm Detector Technology Workshop.
Abstract: During the past decade major advances have been made regarding low noise mixers for terahertz (THz) heterodyne receivers. State of the art hot-electron-bolometer (HEB) mixers have noise temperatures close to the quantum limit and require less than a µW power from the local oscillator (LO). The technology is now at a point where the performance of a practical receiver employing such mixer, rather than the figures of merit of the mixer itself, are of major concern. We have incorporated a phonon-cooled NbN HEB mixer in a 2.5 THz heterodyne receiver and investigated the performance of the receiver. This yields important information for the development of heterodyne receivers such as GREAT (German receiver for astronomy at THz frequencies aboard SOFIA)[1] and TELIS (Terahertz limb sounder), a balloon borne heterodyne receiver for atmospheric research [2]. Both are currently under development at DLR.
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Zhou, Y. D., Becker, C. R., Ashokan, R., Selamet, Y., Chang, Y., Boreiko, R. T., et al. (2002). Progress in far-infrared detection technology. In Proc. SPIE (Vol. 4795, pp. 121–128). Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series.
Abstract: II-VI intrinsic very long wavelength infrared (VLWIR, λc~20 to 50 μm) materials, HgCdTe alloys as well as HgCdTe/CdTe superlattices, were grown by molecular beam epitaxy (MBE). The layers were characterized by means of X-ray diffraction, conventional Fourier transform infrared spectroscopy, Hall effect measurements and transmittance electron microscopy (TEM). Photoconductor devices were processed and their spectral response was also measured to demonstrate their applicability in the VLWIR region.
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Semenov, A. D., Gol'tsman, G. N., & Sobolewski, R. (2002). Hot-electron effect in superconductors and its applications for radiation sensors. Supercond. Sci. Technol., 15(4), R1–R16.
Abstract: The paper reviews the main aspects of nonequilibrium hot-electron phenomena in superconductors and various theoretical models developed to describe the hot-electron effect. We discuss implementation of the hot-electron avalanche mechanism in superconducting radiation sensors and present the most successful practical devices, such as terahertz mixers and direct intensity detectors, for far-infrared radiation. Our presentation also includes the novel approach to hot-electron quantum detection implemented in superconducting x-ray to optical photon counters.
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Uzawa, Y., Miki, S., Wang, Z., Kawakami, A., Kroug, M., Yagoubov, P., et al. (2002). Performance of a quasi-optical NbN hot-electron bolometric mixer at terahertz frequencies. Supercond. Sci. Technol., 15(1), 141–145.
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Kawamura, J., Hunter, T. R., Tong, C. Y. E., Blundell, R., Papa, D. C., Patt, F., et al. (2002). Ground-based terahertz CO spectroscopy towards Orion. A&A, 394(1), 271–274.
Abstract: Using a superconductive hot-electron bolometer heterodyne receiver on the 10-m Heinrich Hertz Telescope on Mount Graham, Arizona, we have obtained velocity-resolved 1.037 THz CO () spectra toward several positions along the Orion Molecular Cloud (OMC-1) ridge. We confirm the general results of prior observations of high-J CO lines that show that the high temperature, , high density molecular gas, , is quite extended, found along a ~ region centered on BN/KL. However, our observations have significantly improved angular resolution, and with a beam size of we are able to spatially and kinematically discriminate the emission originating in the extended quiescent ridge from the very strong and broadened emission originating in the compact molecular outflow. The ridge emission very close to the BN/KL region appears to originate from two distinct clouds along the line of sight with and ≈ . The former component dominates the emission to the south of BN/KL and the latter to the north, with a turnover point coincident with or near BN/KL. Our evidence precludes a simple rotation of the inner ridge and lends support to a model in which there are multiple molecular clouds along the line of sight towards the Orion ridge.
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Benford, D. J., Moseley, S. H., & Chervenak, J. A. (2002). Mission requirements for ultralow-background, large format bolometer arrays. In Proc. Far-Infrared Submillimeter, & Millimeter Detector Workshop. Monterey, California.
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Verevkin, A., Gershenzon, E. M., Gol'tsman, G. N., Ptitsina, N. G., Chulkova, G. M., Smirnov, K. S., et al. (2002). Direct measurements of energy relaxation times in two-dimensional structures under quasi-equilibrium conditions. In Mater. Sci. Forum (Vol. 384-3, pp. 107–116).
Abstract: A new microwave technique was successfully applied for direct studies of energy relaxation times in two-dimensional AlGaAs/GaAs structures under quasi-equilibrium conditions in the nanosecond and picosecond time scale. We report our results of energy relaxation time measurements in the temperature range 1.6-50 K, in quantum Hall effect regime in magnetic fields up to 4 T.
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Omar, A., Anantharamaiah, K. R., Rupen, M., & Rigby, J. (2002). VLA detection of OH absorption from the elliptical galaxy NGC 1052. A&A, 381(1), L29–L32.
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Maslennikov, S., Antipov, S., Shishkov, A., Svechnikov, S., Voronov, B., Smirnov, K., et al. (2002). NbN HEB mixer noise temperature measurements with hot/cold load mounted inside the helium cryostat at 300 GHz. In Proc. Int. Student Seminar on Microwave Appl. of Novel Physical Phenomena supported by IEEE. St.-Petersburg: LETI.
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