Heterodyne detection and generation of microwave radiation by superconducting microbridges in a resonant structure

А.П. Крутько, V. S. Sulima

M. B. Stern

Dai Yuan-Dong, W. J. Yeh, Y. H. Kao

Vladimir N. Gubankov, V. P. Koshelets, G. A. Ovsiannikov

The temperature and field variation of the photoresponse of tin Josephson film microbridges are studied in experiments in which the microbridges are irradiated in the centimeter and millimeter ranges. Experiments have been carried out under conditions that correspond to narrow-band and wide-band detection. Certain features of the response which are due to stimulation of superconductivity in the microbridges by the microwave radiation and a direct current are studied. In heterodyne detection these features disappear at a high power level of the heterodyne oscillator, and a substantial increase is observed in the response, this is caused by a higher differential resistance of the microbridge. The maximum sensitivity (approx.10/sup 4/ V/W) is achieved with selective detection.

Charles Neill, A. Megrant, M. Lenander +17 more

Alexei D. Semenov, Yu. P. Gousev, Rainer S. Nebosis +6 more

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.