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Gershenzon, E. M., Gershenzon, M. E., Goltsman, G. N., Semenov, A. D., & Sergeev, A. V. (1991). Wide-band highspeed Nb and YBaCuO detectors. IEEE Trans. Magn., 27(2), 2836–2839.
Abstract: The physical limitations on the response time and the nature of nonequilibrium detection of radiation were investigated for Nb and YBCO film in a wide spectral range from millimeter to near-infrared wavelengths. In the case of ideal heat removal from the film, the detection mechanism is connected with an electron heating effect which is not selective over a wide spectral interval. For Nb, the dependence of the response time on the electron mean free path l and temperature T is tau varies as T/sup -2/l/sup -1/. The values of detectivity D* and tau are 3*10/sup 11/ W/sup -1/ Hz/sup 1/2/ cm and 5*10/sup -9/ s at T=1.6 K, respectively. For YBCO film the tau value of 1-2 ps at T=77 K was obtained; the NEP value of 3*10/sup -11/ W-Hz/sup -1/2/ can be obtained at T=77 K in the case of the optimal film matching to the radiation.
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Gol'tsman, G. N., Semenov, A. D., Gousev, Y. P., Zorin, M. A., Gogidze, I. G., Gershenzon, E. M., et al. (1991). Sensitive picosecond NbN detector for radiation from millimetre wavelengths to visible light. Supercond. Sci. Technol., 4(9), 453–456.
Abstract: The authors report on the application of a broad-band NbN film detector which has high sensitivity and picosecond response time for detection of radiation from millimetre wavelengths to visible light. From a study of amplitude modulated radiation of backward-wave tubes and picosecond pulses from gas and solid state lasers at wavelengths between 2 mm and 0.53 mu m, they found a detectivity of 1010 W-1 cm Hz-1/2 and a response time of less than 50 ps at T=10 K. The characteristics were provided by using a 150 AA thick NbN film patterned into a structure of micron strips. According to the proposed detection mechanism, namely electron heating, they expect an intrinsic response time of approximately 20 ps at the same temperature.
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Gershenzon, E. M., Gol’tsman, G. N., Gousev, Y. P., Elant’ev, A. I., & Semenov, A. D. (1991). Electromagnetic radiation mixer based on electron heating in resistive state of superconductive Nb and YBaCuO films. IEEE Trans. Magn., 27(2), 1317–1320.
Abstract: A theory of an electron-heating mixer which makes it possible to calculate all the characteristics of the device is developed. It is shown that positive conversion gain is possible for such a mixer in the millimeter to near-infrared wavelength range. The dynamic range and the optimum heterodyne power can be selected from a very wide interval by varying the mixing element volume. Measurements made for Nb within the frequency range of 120-750 GHz confirm the theory. The conversion loss obtained at T=1.6 K and normalized to the element reaches 0.3 dB in the intermediate frequency band of 40 MHz; the possible noise temperature is 50 K. The estimation of noise temperature and output band for YBaCuO at T=77 yields 200 K and more than 10 GHz, respectively.
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Gershenzon, E. M., Gol'tsman, G. N., Gogidze, I. G., Semenov, A. D., & Sergeev, A. V. (1991). Processes of electron-phonon interaction in thin YBaCuO films. Phys. C: Supercond., 185-189, 1371–1372.
Abstract: The ultrafast voltage response of YBaCuO films to laser radiation is studied and compared with previously investigated quasiparicles response to radiation of submillimeter wavelength range. Voltage shift under the visible light radiation has two components. Picosecond response realized as suppression superconductivity by nonequilibrium excess quasiparticles, response time is determined by quasiparticles recombination rate. Nanosecond response is probably due to bolometric effect.
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Bespalov, A. V., Gol'tsman, G. N., Semenov, A. D., & Renk, K. F. (1991). Determination of the far-infrared emission characteristic of a cyclotron p-germanium laser by use of a superconducting Nb detector. Solid State Communications, 80(7), 503–506.
Abstract: We studied the far-infrared emission characteristics of a cyclotron p-germanium laser using a broad-band superconducting Nb film detector. For magnetic fields between ∼25 kOe and ∼50 kOe, emission in a frequency range from ∼50 cm-1 to ∼100 cm-1 with maximum intensity around 90 cm-1 was obtained. We determined, for fixed magnetic fields, electric field dependences of the emission intensity taking into account that the total electric field is a sum of the applied and the Hall electric field. An analysis of the emission intensity characteristic gives evidence that transitions between the two lowest Landau levels of light holes are responsible for the laser action.
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Lang, P. T., Leipold, I., Knott, W. J., Semenov, A. D., Gol'tsman, G. N., & Renk, K. F. (1991). New far-infrared laser lines from CH3Cl and CH3Br optically pumped with a continuously tunable high pressure CO2 laser. Appl. Phys. B, 53(4), 207–212.
Abstract: In this paper we report on the detection of new far-infrared laser lines from CH3Cl and CH3Br optically pumped with a continuously tunable high pressure CO2 laser. We found 80 new lines for CH3Cl and 9 new lines for CH3Br in the frequency region between 16 cm−1 and 41 cm−1, all due to stimulated Raman scattering. For the Raman gain regions bandwidths up to about 700 MHz were found. We also observed high intensity short far-infrared laser pulses of durations in the nanosecond regime.
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Gershenzon, E. M., Gol’tsman, G. N., Semenov, A. D., & Sergeev, A. V. (1991). Mechanism of picosecond response of granular YBaCuO films to electromagnetic radiation. IEEE Trans. Magn., 27(2), 1321–1324.
Abstract: Ultrafast mechanisms of radiation detection in granular YBaCuO films are studied in the wide wavelength range from millimeter waves to near infrared. With an increase in radiation frequency, the Josephson detection at the grain-boundary weak links is replaced by electron heating into the grains. This change occurs in the submillimeter wavelength range. The electron-phonon relaxation time tau /sub eph/ is determined from direct measurements, quasi-stationary electron heating measurements, and the frequency dependence of the current at which maximum voltage shift is observed. The temperature dependence of tau /sub eph/ at T<or=40 K was found to be tau /sub eph/ approximately T/sup -1/. The results show that detectors with a response time of a few picoseconds at nitrogen temperature are attainable.
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Aksaev, E. E., Gershenzon, E. M., Gol'tsman, G. N., Mirskij, G. I., & Semenov, A. D. (1991). Submillimetric spectrometer-relaxometer based on backward-wave tubes with picosecond time resolution. Pribory i Tekhnika Eksperimenta, 34(2), 125–131.
Abstract: The high-sensitive automatic spectrometer-relaxometer based on backward-wave tubes in the range of 4÷0.25 mm was described permitting to study the response kinetics of sample under investigation in any point of this range with the resolution time of 10-11 s. The relaxation measurements were conducted using oscillation beats of two adequate tubes, the frequency of one of them was fixed, while that of the other one was changeable. The amplitude-frequency characteristic of the response under the conditions of synchronous reception was recorded at beat frequency variation from 107 to 1010 Hz. The high sensitivity was reached by decreasing the device recording band down to 100 Hz in the whole measuring range.
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Gershenzon, E. M., Gogidze, I. G., Goltsman, G. N., Semenov, A. D., & Sergeev, A. V. (1991). Picosecond response on optical-range emission in thin YBaCuO films. Pisma v Zhurnal Tekhnicheskoi Fiziki, 17(22), 6–10.
Abstract: Целью настоящей работы является целенаправленный поиск пико-секундного отклика на оптическое излучение выяснение оптимальных условий его наблюдения, а также сравнение характеристик неравновесных эффектов в оптическом и субмиллиметровом диапазонах.
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Gershenzon, E. M., Gol'tsman, G. N., Semenov, A. D., & Sergeev, A. V. (1992). Heating of electrons in resistive state of superconducting films. Detectors, mixers and switches. In Progress in High Temperature Superconductivity (Vol. 32, pp. 190–195).
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Nebosis, R. S., Steinke, R., Lang, P. T., Schatz, W., Heusinger, M. A., Renk, K. F., et al. (1992). Picosecond YBa2Cu3O7−δdetector for far‐infrared radiation. J. Appl. Phys., 72(11), 5496–5499.
Abstract: We report on a picosecond YBa2Cu3O7−δ detector for far‐infrared radiation. The detector, consisting of a current carrying structure cooled to liquid‐nitrogen temperature, was studied by use of ultrashort laser pulses from an optically pumped far‐infrared laser in the frequency range from 25 to 215 cm−1. We found that the sensitivity (1 mV/W) was almost constant in this frequency range. We estimated a noise equivalent power of less than 5×10−7 W Hz−1/2. Taking into account the results of a mixing experiment (in the frequency range from 4 to 30 cm−1) we suggest that the response time of the detector was few picoseconds.
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Voronov, B. M., Gershenzon, E. M., Gol'tsman, G. N., Gogidze, I. G., Gusev, Y. P., Zorin, M. A., et al. (1992). Picosecond range detector base on superconducting niobium nitride film sensitive to radiation in spectral range from millimeter waves up to visible light. Sverkhprovodimost': Fizika, Khimiya, Tekhnika, 5(5), 955–960.
Abstract: Fast-operating picosecond detector of electromagnetical radiation is developed on the basis of fine superconducting film of niobium nitride with high sensitivity within spectral range from millimetric waves up to visible light. Detector sensitive element represents structure covering narrow parallel strips with micron sizes included in the rupture of microstrip line. Detecting ability of the detector and time constant measured using amplitude-simulated radiation of reverse wave tubes and pulse radiation of picosecond gas and solid-body lasers, constitute D*≅1010 W-1·cm·Hz-1/2 and τ≤5 ps respectively, at 10 K temperature. The expected value of time constant of the detector at 10 K obtained via extrapolation of directly measured dependence that is, τ ∝ τ-1, constitutes 20 ps. Experimental data demonstrate that detection mechanism is linked with electron heating effect.
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Lang, P. T., Knott, W. J., Leipold, I., Renk, K. F., Semenov, A. D., & Gol'tsman, G. N. (1992). Generation and detection of tunable ultrashort infrared and far-infrared radiation pulses of high intensity. Int. J. of Infrared and Millimeter Waves, 13(3), 373–380.
Abstract: We report on generation and detection of intense pulsed radiation with frequency tunability in the infrared and far-infrared spectral regions. Infrared radiation is generated with a transversally electrically excited high pressure CO2 laser. A laser pulse of a total duration of about 300 ns consisted, due to self mode locking, of a series of single pulses, some with pulse durations of less than 450 ps and peak powers larger than 20 MW. Using these pulses for optical with durations less than 400 ps were obtained. For detection a new ultrafast superconducting detector was used.
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Semenov, A. D., Gol’tsman, G. N., Gogidze, I. G., Sergeev, A. V., Gershenzon, E. M., Lang, P. T., et al. (1992). Subnanosecond photoresponse of a YBaCuO thin film to infrared and visible radiation by quasiparticle induced suppression of superconductivity. Appl. Phys. Lett., 60(7), 903–905.
Abstract: We observed subnanosecond photoresponse of a structured superconducting YBa2Cu3O7−δ thin film to infrared and visible radiation. We measured the voltage response of a current biased film (thickness 700 Å) in a resistive state to radiation pulses. From our results we conclude a response time of about 90 ps and a responsivity of about 4×1010 Ω/J. We attribute the response to Cooper pair breaking and suppression of the superconducting energy gap induced by nonequilibrium quasiparticles.
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Gershenzon, E. M., Gol'tsman, G. N., Dzardanov, A. L., Elant'ev, A. I., Zorin, M. A., Markin, A. G., et al. (1992). S-N switching of niobium and YBCO films: limit time and perspective of fast key element creation. Sverkhprovodimost': Fizika, Khimiya, Tekhnika, 5(12), 2386–2402.
Abstract: A study was made on processes of switching of thin niobium film strips between superconducting and normal states under the effect of optical radiation pulse and voltage step. The results are described satisfactorily by the model of spatial homogeneous electron heating. It is shown that limiting switching times can be equal to several shares of nanosecond at 4.2 K. Preliminary results for YBa2Cu3O-7-x films are presented. Prospects and advantages of creation of ducting structures of narrow streps, are discussed.
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