An Ultra-violet Heterodyne System For Evaluating Photomixers

Abstract

A heterodyne system for measuring frequency response, quantum efficiency, and NEP of ultraviolet photomixers has been developed. The system incorporates a large frame Ar-ion laser local oscillator (A = 334.5 nm) and a frequency-doubled tunable dye laser signal source. The system is amplifier limited to a DC to 10GHz bandwidth. The photomixer is mounted on a computerized X-Y-Z stage with O.l-pm resolution. Absolute frequency response characteristics of threedetectors, one fabricated in house, are presented. DC and rf response as a function of beam position on the detector surface are also presented.