Karasik, B. S., Lindgren, M., Zorin, M. A., Danerud, M., Winkler, D., Trifonov, V. V., et al. (1994). Picosecond detection and broadband mixing of near-infrared radiation by YBaCuO films. In M. Nahum, & J. - C. Villegier (Eds.), Proc. SPIE (Vol. 2159, pp. 68–76). Spie.
Abstract: Nonequilibrium picosecond and bolometric responses of YBCO films 500 angstroms thick patterned into 20 X 20 micrometers 2 size structure to 17 ps laser pulses and modulated radiation of GaAs and CO2 lasers have been studied. The modulation frequencies up to 10 GHz for GaAs laser and up to 1 GHz for CO2 were attained. The use of small radiation power (1 – 10 mW/cm2 for cw radiation and 10 – 100 nJ/cm2 for pulse radiation) in combination with high sensitive read-out system made possible to avoid any non-linear transient processes caused by an overheating of sample above a critical temperature or S-N switching enhanced by an intense radiation. Responses due to the change of kinetic inductance were believed to be negligible. The only signals observed were caused by a small change of the film resistance either in the resistive state created by a bias current or in the normal state. The data obtained by means of pulse and modulation techniques are in agreement. The responsivity about 1 V/W was measured at 1 GHz modulation frequency both for 0.85 micrometers and 10.6 micrometers wavelengths. The sensitivity of high-Tc fast wideband infrared detector is discussed.
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Gol’tsman, G. N., Kouminov, P. B., Goghidze, I. G., Karasik, B. S., & Gershenzon, E. M. (1994). Nonbolometric and fast bolometric responses of YBaCuO thin films in superconducting, resistive, and normal states. In M. Nahum, & J. - C. Villegier (Eds.), Proc. SPIE (Vol. 2159, pp. 81–86). SPIE.
Abstract: The transient voltage response in both epitaxial and granular YBaCuO thin films to 20 ps pulses of YAG:Nd laser radiation with 0.63 micrometers and 1.54 micrometers was studied. In normal and resistive states both types of films demonstrate two components: nonequilibrium picosecond component and following bolometric nanosecond. The normalized amplitudes are almost the same for all films. In superconducting state we observed a kinetic inductive response and two-component shape after integration. The normalized amplitude of the response in granular films is up to several orders of magnitude larger than in epitaxial films. We interpret the nonequilibrium response in terms of a suppression of order parameter by the excess of quasiparticles followed by the change of resistance in normal and resistive states or kinetic inductance in superconducting state. The sharp rise of inductive response in granular films is explained both by a diminishing of the crossection for current percolation through the disordered network os Josephson weak links and by a decrease of condensate density in neighboring regions.
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Danerud, M., Winkler, D., Zorin, M., Trifonov, V., Karasik, B., Gershenzon, E. M., et al. (1993). Picosecond detection of infrared radiation with YBa2Cu3O7-δ thin films. In J. R. Birch, & T. J. Parker (Eds.), Proc. SPIE (Vol. 2104, pp. 183–184). Spie.
Abstract: Picosecond nonequilibrium and slow bolometric responses from a patterned high-Tc superconducting (HTS) film due toinfrared radiation were investigated using both modulation and pulse techniques. Measurements at A, = 0.85 [tm andA, = 10.6 lim have shown a similar behaviour of the response vs modulation frequency f. The responsivity of the HTS filmbased detector at f ..- 0.6-1 GHz is estimated to be 10-2 – 10-1 V/W.
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Lindgren, M., Zorin, M. A., Trifonov, V., Danerud, M., Winkler, D., Karasik, B. S., et al. (1994). Optical mixing in a patterned YBa2Cu3O7-δ thin film. Appl. Phys. Lett., 65(26), 3398–3400.
Abstract: Mixing of 1.56 µm infrared radiation from two lasers in a high quality YBa2Cu3O7-δ thin film, patterned to parallel strips, was demonstrated. A mixer bandwidth of 18 GHz, limited by the measurement system, was obtained. A model based on nonequilibrium electron heating gives a good fit to the data and predicts an intrinsic mixer bandwidth in excess of 100 GHz, operating in the whole infrared spectrum. Reduction of bolometric effects and ways to decrease the conversion loss of the mixer is discussed. The minimum conversion loss is expected to be ~10 dB.
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Cherednichenko, S., Rönnung, F., Gol'tsman, G., Kollberg, E., & Winkler, D. (2000). YBa2Cu3O7−δ hot-electron bolometer mixer. Phys. C: Supercond., 341-348, 2653–2654.
Abstract: We present an investigation of hot-electron bolometric mixer based on YBa2Cu3O7−δ (YBCO) superconducting thin film. Mixer conversion loss, absorbed local oscillator power and intermediate frequency bandwidth was measured at the local oscillator frequency 600 GHz. The fabrication technique for nanoscale YBCO hot-electron bolometer (HEB) mixer integrated into planar antenna structure is described.
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