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Jackson BD, Baryshev AM, de Lange G, Gao JR, Shitov SV, Iosad NN, et al. Low-noise 1 THz superconductor-insulator-superconductor mixer incorporating a NbTiN/SiO2/Al tuning circuit. Appl. Phys. Lett.. 2001;79(3):436.
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Karpov A, Miller D, Rice F, Zmuidzinas J, Stern JA, Bumble B, et al. Low noise 1.2 THz SIS receiver. In: Jet Propulsion Laboratory CIit.u.t.e of T, editor. Proc. 12th Int. Symp. Space Terahertz Technol. San Diego, CA, USA; 2001. p. 21–2.
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Kasparek W, Fernandez A, Hollmann F, Wacker R. Measurements of ohmic losses of metallic reflectors at 140 GHz using a 3-mirror resonator technique. Int. J. Infrared and Millimeter Waves. 2001;22(11):1695–707.
Abstract: The reflectivity of metallic mirrors in the millimeter wave region does not only depend on the material, but also on the structure and roughness of the surface. We have performed measurements of the reflectivity of various plane and grooved metallic and graphite samples at 140 GHz. The technique is based on the comparison of the quality factor of a 2-mirror reference resonator with the quality factor of a 3-mirror resonator which has identical dimensions and includes the mirror to be tested. After a brief presentation of the theory, the set-up is described and the reflection loss for various aluminium and copper mirrors as well as vacuum compatible materials for applications in thermonuclear fusion experiments are presented and discussed.
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Kawamura J, Tong C-YE, Blundell R, Papa DC, Hunter TR, Patt F, et al. Terahertz-frequency waveguide NbN hot-electron bolometer mixer. IEEE Trans Appl Supercond. 2001;11(1):952–4.
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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Kroug M. Hot electron bolometric mixers for a quasi-optical terahertz receiver [Ph.D. thesis]. Chalmers University of Technology, Gothenburg, Sweden; 2001.
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Kroug M, Cherednichenko S, Choumas M, Merkel H, Kollberg E, Hübers H-W, et al. HEB quasi-optical heterodyne receiver for THz frequencies. In: Proc. 12th Int. Symp. Space Terahertz Technol. San Diego, CA, USA; 2001. p. 244–52.
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Kroug M, Cherednichenko S, Merkel H, Kollberg E, Voronov B, Gol'tsman G, et al. NbN hot electron bolometric mixers for terahertz receivers. IEEE Trans Appl Supercond. 2001;11(1):962–5.
Abstract: Sensitivity and gain bandwidth measurements of phonon-cooled NbN superconducting hot-electron bolometer mixers are presented. The best receiver noise temperatures are: 700 K at 1.6 THz and 1100 K at 2.5 THz. Parylene as an antireflection coating on silicon has been investigated and used in the optics of the receiver. The dependence of the mixer gain bandwidth (GBW) on the bias voltage has been measured. Starting from low bias voltages, close to operating conditions yielding the lowest noise temperature, the GBW increases towards higher bias voltages, up to three times the initial value. The highest measured GBW is 9 GHz within the same bias range the noise temperature increases by a factor of two.
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Mel’nikov AP, Gurvich YA, Shestakov LN, Gershenzon EM. Magnetic field effects on the nonohmic impurity conduction of uncompensated crystalline silicon. Jetp Lett. 2001;73(1):44–7.
Abstract: The impurity conduction of a series of crystalline silicon samples with the concentration of major impurity N ≈ 3 × 1016 cm−3 and with a varied, but very small, compensation K was measured as a function of the electric field E in various magnetic fields H-σ(H, E). It was found that, at K < 10−3 and in moderate E, where these samples are characterized by a negative nonohmicity (dσ(0, E)/dE < 0), the ratio σ(H, E)/σ(0, E) > 1 (negative magnetoresistance). With increasing E, these inequalities are simultaneously reversed (positive nonohmicity and positive magnetoresistance). It is suggested that both negative and positive nonohmicities are due to electron transitions in electric fields from impurity ground states to states in the Mott-Hubbard gap.
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Merkel HF, Khosropanah P, Sigfrid Yngvesson K, Cherednichenko S, Kroug M, Adam A, et al. An active zone small signal model for hot-electron bolometric mixers. In: Proc. 12th Int. Symp. Space Terahertz Technol. San Diego, CA, USA; 2001. 55.
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Murk A, Kämpfer N, Wylde R, Inatani J, Manabe T, Seta M. Characterization of various quasi-optical components for the submillimeter limb-sounder SMILES. In: Proc. 12th Int. Symp. Space Terahertz Technol.; 2001. p. 426–35.
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