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Henry, R. C. (1999). Diffuse background radiation. Astrophys. J., 516(2), L49–L52.
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Burke, P. J., Schoelkopf, R. J., Prober, D. E., Skalare, A., Karasik, B. S., Gaidis, M. C., et al. (1999). Mixing and noise in diffusion and phonon cooled superconducting hot-electron bolometers. J. Appl. Phys., 85(3), 1644–1653.
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Sergeev, A., Karasik, B. S., Ptitsina, N. G., Chulkova, G. M., Il'in, K. S., & Gershenzon, E. M. (1999). Electron–phonon interaction in disordered conductors. Phys. Rev. B Condens. Matter, 263-264, 190–192.
Abstract: The electron–phonon interaction is strongly modified in conductors with a small value of the electron mean free path (impure metals, thin films). As a result, the temperature dependencies of both the inelastic electron scattering rate and resistivity differ significantly from those for pure bulk materials. Recent complex measurements have shown that modified dependencies are well described at K by the electron interaction with transverse phonons. At helium temperatures, available data are conflicting, and cannot be described by an universal model.
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Yagoubov, P., Kroug, M., Merkel, H., Kollberg, E., Schubert, J., & Hübers, H. - W. (1999). NbN hot electron bolometric mixers at frequencies between 0.7 and 3.1 THz. Supercond. Sci. Technol., 12(11), 989–991.
Abstract: The performance of NbN-based phonon-cooled hot electron bolometric (HEB) quasioptical mixers is investigated in the 0.7-3.1 THz frequency range. The devices are made from a 3.5-4 nm thick NbN film on high resistivity Si and integrated with a planar spiral antenna on the same substrate. The length of the bolometer microbridge is 0.1-0.2 µm; the width is 1-2 µm. The best results of the DSB receiver noise temperature measured at 1.5 GHz intermediate frequency are: 800 K at 0.7 THz, 1100 K at 1.6 THz, 2000 K at 2.5 THz and 4200 K at 3.1 THz. The measurements were performed with a far infrared laser as the local oscillator (LO) source. The estimated LO power requirement is less than 500 nW at the receiver input. First results on spiral antenna polarization measurements are reported.
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Il'in, K. S., Verevkin, A. A., Gol'tsman, G. N., & Sobolewski, R. (1999). Infrared hot-electron NbN superconducting photodetectors for imaging applications. Supercond. Sci. Technol., 12(11), 755–758.
Abstract: We report an effective quantum efficiency of 340, responsivity >200 A W-1 (>104 V W-1) and response time of 27±5 ps at temperatures close to the superconducting transition for NbN superconducting hot-electron photodetectors (HEPs) in the near-infrared and optical ranges. Our studies were performed on a few nm thick NbN films deposited on sapphire substrates and patterned into µm-size multibridge detector structures, incorporated into a coplanar transmission line. The time-resolved photoresponse was studied by means of subpicosecond electro-optic sampling with 100 fs wide laser pulses. The quantum efficiency and responsivity studies of our photodetectors were conducted using an amplitude-modulated infrared beam, fibre-optically coupled to the device. The observed picosecond response time and the very high efficiency and sensitivity of the NbN HEPs make them an excellent choice for infrared imaging photodetectors and input optical-to-electrical transducers for superconducting digital circuits.
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