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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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Semenov AD, Heusinger MA, Renk KF, Menschikov E, Sergeev AV, Elant'ev AI, et al. Influence of phonon trapping on the performance of NbN kinetic inductance detectors. IEEE Trans Appl Supercond. 1997;7(2):3083–6.
Abstract: Voltage and microwave photoresponse of NbN thin films to modulated and pulsed optical radiation reveals, far below the superconducting transition, a response time consistent with the lifetime of nonequilibrium quasiparticles. We show that even in 5 nm thick films at 4.2 K the phonon trapping is significant resulting in a quasiparticle lifetime of a few nanoseconds that is an order of magnitude larger than the recombination time. Values and temperature dependence of the quasiparticle lifetime obey the Bardeen-Cooper-Schrieffer theory and are in quantitative agreement with the electron-phonon relaxation rate determined from the resistive response near the superconducting transition. We discuss a positive effect of the phonon trapping on the performance of kinetic inductance detectors.
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Karasik BS, Milostnaya II, Zorin MA, Elantev AI, Gol'tsman GN, Gershenzon EM. High speed current switching of homogeneous YBaCuO film between superconducting and resistive states. IEEE Trans Appl Supercond. 1995;5(2):3042–5.
Abstract: Transitions of thin structured YBaCuO films from superconducting (S) to normal (N) state and back induced by a supercritical current pulse has been studied. A subnanosecond stage in the film resistance dynamic has been observed. A more gradual (nanosecond) ramp in the time dependence of the resistance follows the fast stage. The fraction of the film resistance which is attained during the fast S-N stage rises with the current amplitude. Subnanosecond N-S switching is more pronounced for smaller amplitudes of driving current and for shorter pulses. The phenomena observed are viewed within the framework of an electron heating model. The expected switching time and repetition rate of an optimized current controlling device are estimated to be 1-2 ps and 80 GHz respectively.
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Karasik BS, Gol'tsman GN, Voronov BM, Svechnikov SI, Gershenzon EM, Ekstrom H, et al. Hot electron quasioptical NbN superconducting mixer. IEEE Trans Appl Supercond. 1995;5(2):2232–5.
Abstract: Hot electron superconductor mixer devices made of thin NbN films on SiO/sub 2/-Si/sub 3/N/sub 4/-Si membrane have been fabricated for 300-350 GHz operation. The device consists of 5-10 parallel strips each 5 /spl mu/m long by 1 /spl mu/m wide which are coupled to a tapered slot-line antenna. The I-V characteristics and position of optimum bias point were studied in the temperature range 4.5-8 K. The performance of the mixer at higher temperatures is closer to that predicted by theory for uniform electron heating. The intermediate frequency bandwidth versus bias has also been investigated. At the operating temperature 4.2 K a bandwidth as wide as 0.8 GHz has been measured for a mixer made of 6 nm thick film. The bandwidth tends to increase with operating temperature. The performance of the NbN mixer is expected to be better for higher frequencies where the absorption of radiation should be more uniform.
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Gershenzon EM, Gol'tsman GN, Elant'ev AI, Karasik BS, Potoskuev SE. Intense electromagnetic radiation heating of superconductor electrons in resistive state. Fizika Nizkikh Temperatur. 1988;14(7):753–63.
Abstract: An experimental study is made of the effect of intense radiation in the millimeter and submillimeter ranges on thin and narrow Nb films in the resistive state. It is found that the excess resistance resulting from radiation and the dependence of its relaxation time on radiation intensity and transport current can be explained in terms of the effect of electron heating. Quantitative agreement is obtained between the experimental data and a homogeneous electron heating model.
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Blagosklonskaya LE, Gershenzon EM, Gol'tsman GN, Elant'ev AI. Effect of a high magnetic field on the spectrum of donors in InSb. Fizika i Tekhnika Poluprovodnikov. 1977;11(12):2373–5.
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Zhang J, Boiadjieva N, Chulkova G, Deslandes H, Gol'tsman GN, Korneev A, et al. Noninvasive CMOS circuit testing with NbN superconducting single-photon detectors. Electron Lett. 2003;39(14):1086–8.
Abstract: The 3.5 nm thick-film, meander-structured NbN superconducting single-photon detectors have been implemented in the CMOS circuit-testing system based on the detection of near-infrared photon emission from switching transistors and have significantly improved the performance of the system. Photon emissions from both p- and n-MOS transistors have been observed.
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Il'in KS, Karasik BS, Ptitsina NG, Sergeev AV, Gol'tsman GN, Gershenzon EM, et al. Electron-phonon-impurity interference in thin NbC films: electron inelastic scattering time and corrections to resistivity. In: Czech. J. Phys. Vol 46.; 1996. p. 857–8.
Abstract: Complex study of transport properties of impure NbC films with the electron mean free pathl=0.6–13 nm show the crucial role of the electron-phonon-impurity interference (EPII). In the temperature range 20–70 K we found the interference correction to resistivity proportional to T2 and to the residual resistivity of the film. Using the comprehensive theory of EPII, we determine the electron coupling with transverse phonons and calculate the electron inelastic scattering time. Direct measurements of the inelastic electron scattering time using a response to a high-frequency amplitude modulated cw radiation agree well with the theory.
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Gershenzon EM, Gol'tsman GN, Zorin MA, Karasik BS, Trifonov VA. Nonequilibrium and bolometric response of YBaCuO films in a resistive state to infrared low intensity radiation. In: Council on Low-temp. Phys.; 1994. p. 82–3.
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Zhang W, Li N, Jiang L, Miao W, Lin Z-H, Yao Q-J, et al. Noise behaviour of a THz superconducting hot-electron bolometer mixer. Chinese Phys Lett. 2007;24(6):1778–81.
Abstract: A quasi-optical superconducting NbN hot-electron bolometer (HEB) mixer is measured in the frequency range of 0.5–2.5 THz for understanding of the frequency dependence of noise temperature of THz coherent detectors. It has been found that noise temperature increasing with frequency is mainly due to the coupling loss between the quasi-optical planar antenna and the superconducting HEB bridge when taking account of non-uniform distribution of high-frequency current. With the coupling loss corrected, the superconducting HEB mixer demonstrates a noise temperature nearly independent of frequency.
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