Optically triggered bulk device gunn oscillator

A high power solid state source of microwave and millimeter wave signals is provided by an optically triggered body of bulk semiconductor material selected from the Group 3 to 5 compounds including GaAs, Cr:GaAs, and Fe:InP and having a relatively long gap length which is in the order of 0.5 to 10.0 mm as well as having a resistivity which is greater than 10 to the 7th power ohm-cm. The device is further dc biased to a field of between 15 kV/cm and 35 kV/cm. Under such conditions, a very low dc current flows without any oscillatory behavior; however, illumination of the semiconductor body with a fast rising optical pulse having a wavelength suitable for carrier generation causes electrons to be lifted to the conduction band which is accompanied by a rapid reduction of the resistivity. At the same time, the electric field across the gap length decreases to a value just above the oscillation threshold whereupon high power RF oscillations are generated whose frequency is a function of the recombination time of the excited carriers.