HETERODYNE-DETECTION OF THZ RADIATION WITH A SUPERCONDUCTING HOT-ELECTRON BOLOMETER MIXER

We report on the use of a superconducting hot-electron bolometer mixer for heterodyne detection of terahertz radiation. Radiation with a wav elength of 119 mu m was coupled to the mixer, a NbN microbridge, by a hybrid quasioptical antenna consisting of an extended hyperhemispheric al lens and a planar logarithmic spiral antenna. We found, at an inter mediate frequency of 1.5 GHz, a system double side band noise temperat ure of approximate to 40 000 K and conversion losses of 25 dB. We also discuss the possibilities of further improvement of the mixer perform ance. (C) 1996 American Institute of Physics.