A microprocessor stabilized submillimeter laser system

A mechanically and thermally stable submillimeter laser has been constructed and has an amplitude and frequency stability suitable for use as a local oscillator in a heterodyne receiver for astronomical investigations. The microprocessor stabilization reduces the receiver noise for different kinds of Schottky barrier diodes used. A short-time amplitude stability (10 minutes) of about ±0.5% and a long time amplitude stability (1 hour) of about ±1.2% have been recorded. Integration times up to one hour with a spectral resolution better than 200 KHz are possible with such a stabilized system.