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Semenov AD, Gousev YP, Nebosis RS, Renk KF, Yagoubov P, Voronov BM, et al. Heterodyne detection of THz radiation with a superconducting hot‐electron bolometer mixer. Appl Phys Lett. 1996;69(2):260–2.
Abstract: We report on the use of a superconducting hot‐electron bolometer mixer for heterodyne detection of terahertz radiation. Radiation with a wavelength of 119 μm was coupled to the mixer, a NbN microbridge, by a hybrid quasioptical antenna consisting of an extended hyperhemispherical lens and a planar logarithmic spiral antenna. We found, at an intermediate frequency of 1.5 GHz, a system double side band noise temperature of ≊40 000 K and conversion losses of 25 dB. We also discuss the possibilities of further improvement of the mixer performance.
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Gershenzon EM, Gershenzon ME, Gol'tsman GN, Semyonov AD, Sergeev AV. Heating of electrons in superconductor in the resistive state due to electromagnetic radiation. Solid State Communications. 1984;50(3):207–12.
Abstract: The effect of heating electrons with respect to phonons in a thin superconducting film driven into the resistive state by the current and the external magnetic field has been observed and investigated. This effect caused by the electromagnetic radiation is manifested in the increased resistance of the film and is not selective over the frequency range from 1010 to 1015 Hz. That the effect is frequency independent under the conditions of strong electron scattering caused by static defects is explained by the decisive role of electron -electron collisions in forming the distribution function. The characteristic time of resistance change, obtained experimentally, corresponds to the relaxation time of the order parameter near the superconducting transition and to the relaxation time of the nonelastic electron-phonon interaction at lower temperatures and in lower magnetic fields.
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Gershenzon EM, Gol'tsman GN, Semenov AD, Sergeev AV. Heating of electrons in resistive state of superconducting films. Detectors, mixers and switches. In: Progress in High Temperature Superconductivity. Vol 32.; 1992. p. 190–5.
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Gershenzon EM, Gershenzon ME, Gol'tsman GN, Semenov AD, Sergeev AV. Heating of electrons in a superconductor in the resistive state by electromagnetic radiation. Sov Phys JETP. 1984;59(2):442–50.
Abstract: The effect of heating of electrons relative to phonons is observed and investigated in a superconducting film that is made resistive by current and by an external magnetic field. The effect is manifested by an increase of the film resistance under the influence of the electromagnetic radiation, and is not selective in the frequency band 10^10-10^15 Hz. The independence of the effect of frequency under conditions of strong scattering by static defects is attributed to the decisive role of electron-electron collisions in the distribution function. The experimentally obtained characteristic time of resistance variation near the superconducting transition corresponds to the relaxation time of the order parameter, while at lower temperatures and fields it corresponds to the time of the inelastic electron-phonon interaction.
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Gershenzon EM, Goltsman G, Orlova S, Ptitsina N, Gurvich Y. Germanium hot-electron narrow-band detector. Sov Radio Engineering And Electronic Physics. 1971;16(8):1346.
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Semenov AD, Hübers H–W, Schubert J, Gol'tsman GN, Elantiev AI, Voronov BM, et al. Frequency dependent noise temperature of the lattice cooled hot-electron terahertz mixer. In: Proc. 11th Int. Symp. Space Terahertz Technol.; 2000. p. 39–48.
Abstract: We present the measurements and the theoretical model on the frequency dependent noise temperature of a lattice cooled hot electron bolometer (HEB) mixer in the terahertz frequency range. The experimentally observed increase of the noise temperature with frequency is a cumulative effect of the non-uniform distribution of the high frequency current in the bolometer and the charge imbalance, which occurs near the edges of the normal domain and contacts with normal metal. In addition, we present experimental results which show that the noise temperature of a HEB mixer can be reduced by about 30% due to a Parylene antireflection coating on the Silicon hyperhemispheric lens.
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Gershenzon EM, Gershenson ME, Goltsman GN, Karasik BS, Lyulkin AM, Semenov AD. Fast-response superconducting electron bolometer. Pisma v Zhurnal Tekhnicheskoi Fiziki. 1989;15(3):88–92.
Abstract: The general design, operation, and performance characteristics of fast-response electronic bolometers using a thin superconducting Nb film on a leucosapphire substrate are briefly reviewed. The volt-watt sensitivity of the bolometrs is 2,000-200,000 V/W, the operating temperature is 1.6 K, and the time constant is 4-4.5 ns.
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Zorin M, Milostnaya I, Gol'tsman GN, Gershenzon EM. Fast NbN superconducting switch controlled by optical radiation. IEEE Trans Appl Supercond. 1997;7(2):3734–7.
Abstract: The switching time and the optical control power of the NbN superconducting switch have been measured. The device is based on the ultrathin film 5-8 nm thick patterned as a structure of several narrow parallel strips (/spl sim/1 /spl mu/m wide) connected to wide current leads. The current-voltage characteristic of the switch at temperature 4.2 K demonstrated a hysteresis due to DC current self-heating. We studied the superconducting-to-resistive state transition induced by both optical and bias-current excitations. The optical pulse duration was /spl sim/20 ps and the rise time of the current step was determined to be less than 50 ps. The optical pulse was delivered to the switch by the semiconductor laser through an optical fiber. We found that the measured switching time is less than the duration of the optical excitation. The threshold optical power density does not exceed 3/spl middot/10/sup 3/ W/cm/sup 2/. The proposed device can be used in the fiber input of LTS rapid single flux quantum circuits.
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Karasik BS, Zorin MA, Milostnaya II, Elantev AI, Gol’tsman GN, Gershenzon EM. Evidence of subnanosecond transition stage in S-N current switching of YBaCuO films. In: Buhrman RA, Clarke JT, Daly K, Koch RH, Luine JA, Simon RW, editors. Proc. SPIE. Vol 2160. SPIE; 1994. p. 74–82.
Abstract: We report on a study of S-N and N-S current switching in high quality YBaCuO films deposited onto ZrO2 and NdGaO3 substrates. The films 60-120 nm thick prepared by laser ablation were structured into single strips and were provided with gold contacts. We monitored the time dependence of the resistance upon application of the voltage step on the film. Experiment performed within certain ranges of voltage amplitudes and temperatures showed the occurrence of the fast stage both in S-N (shorter than 300 ps) and N-S transition. We discuss the mechanism of switching taking into account the hot electron phenomena in YBaCuO. The contributions of various thermal processes in the subsequent stage of the resistance dynamic are also discussed. The basic limiting characteristics (average dissipated power, minimum work done for switching, maximum repetition rate) of a picosecond switch which is proposed to be developed are estimated.
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Semenov AD, Goghidze IG, Gol’tsman GN, Sergeev AV, Gershenzon EM. Evidence for the spectral dependence of nonequilibrium picosecond photoresponse of YBaCuO thin films. Appl Phys Lett. 1993;63(5):681–3.
Abstract: The transient voltage photoresponse of current biased YBaCuO thin films to 20 ps laser pulses of 0.63 and 1.54 μm wavelengths is measured for temperatures around the superconducting transition region. The fast picosecond decay of the response is followed by a slow nanosecond relaxation which is associated with the bolometric effect. The magnitude of the fast component of the response varies in proportion to the square root of wavelength that plausibly reflects multiplication processes of photoexcited electrons via electron–electron scattering and interaction with high energy phonons.
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