|
|
Gousev YP, Semenov AD, Goghidze IG, Pechen EV, Varlashkin AV, Gol'tsman GN, et al. Current dependent noise in a YBa2Cu3O7-δ hot-electron bolometer. IEEE Trans Appl Supercond. 1997;7(2):3556–9.
Abstract: We investigated the output noise of a YBa2Cu3O7-δ (YBCO) superconducting hot-electron bolometer (HEB) in a large frequency range (10 kHz to 8 GHz); the bolometer either consisted of a structured 50 nm thick YBCO film on LaAlO/sub 3/ or a 30 nm thick film on a MgO substrate. We found that flicker noise dominated at low frequencies (below 1 MHz), while at higher frequencies Johnson noise and a current dependent noise were the main noise sources.
|
|
|
|
Gershenzon EM, Gol’tsman GN, Gousev YP, Elant’ev AI, Semenov AD. Electromagnetic radiation mixer based on electron heating in resistive state of superconductive Nb and YBaCuO films. IEEE Trans Magn. 1991;27(2):1317–20.
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.
|
|
|
|
Gousev YP, Semenov AD, Gol'tsman GN, Sergeev AV, Gershenzon EM. Electron-phonon interaction in disordered NbN films. Phys B Condens Mat. 1994;194-196:1355–6.
Abstract: Electron-phonon interaction time has been investigated in disordered films of NbN. A temperatures below 5.5 K tau_eph ~ T -1"6 which is attributed to the renormalisation of phonon spectrum in thin films.
|
|
|
|
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.
|
|
|
|
Semenov AD, Gousev YP, Renk KF, Voronov BM, Gol'tsman GN, Gershenzon EM, et al. Noise characteristics of a NbN hot-electron mixer at 2.5 THz. IEEE Trans Appl Supercond. 1997;7(2):3572–5.
Abstract: The noise temperature of a NbN phonon cooled hot-electron mixer has been measured at a frequency of 2.5 THz for various operating conditions. We obtained for optimal operation a double sideband mixer noise temperature of /spl ap/14000 K and a system conversion loss of /spl ap/23 dB at intermediate frequencies up to 1 GHz. The dependences of the mixer noise temperature on the bias voltage, local oscillator power, and intermediate frequency were consistent with the phenomenological description based on the effective temperature approximation.
|
|
