Bulk indium antimonide as a microwave-biased millimeter and submillimeter-wave detector

A high-purity n-type indium antimonide sample mounted in a re-entrant cavity and cooled to 4.2°K was operated as a millimeter- and submillimeter-wave detector using a down-conversion process. Power applied at the millimeter-wave frequency causes a change in the material´s conductivity which in turn causes a change in the X-band power absorption, and cavity perturbation techniques were used to analyze the scheme. The detector was operated successfully at frequencies of 35, 60, 80, and 150 GHz with no long-wavelength cutoff frequency observed. A minimum terminal-to-terminal conversion loss and NEP of 11.5 dB and 6.8 × 10^-11W per unit bandwidth, respectively, were measured. The response time is limited by the carrier relaxation time which is of the order of 10^-7s.