USA As Represented by Secretary of the Navy

David C Stoudt

Michael A Richardson

Michael G Grothaus

Jack S Bernardes

Michael S Mazzola

Randy A Roush

A photoconductive switching device is disclosed that has an enhanced speed of response so that its closed (low) and open (high) resistive states are obtained in response to optical illumination in the less than nanosecond regime. The enhanced speed of response is achieved by neutron irradiation of a material preferably comprising GaAs:Si:Cu. An application of the improved photoconductive switching devices is disclosed which allows the realization of a high-power, frequency-agile RF source topology.

Bistable photoconductive switches particularly suited for

A photoconductive switching device is disclosed that has an enhanced speed f response so that its closed (low) and open (high) resistive states are obtained in response to optical illumination in the less than nanosecond regime. The enhanced speed of response is achieved by neutron irradiation of a material preferably comprising GaAs:Si:Cu. An application of the improved photoconductive switching devices is disclosed which allows the realization of a high-power, frequency-agile RF source topology.

Disclosed is a high-voltage, high-current, multichannel, optically-trigge switch with the potential for improved lifetime of operation. Triggering of the switch is accomplished by ultraviolet illumination of multiple cathode apertures via fiber-optic cables. The trigger optics for each channel, being composed of a fiber-optic cable terminated by some collimating optics, are protected from damaging metalization by enclosing them in an angled metal or dielectric tubes in the cathode backspace. The use of collimating optics at the output of the fiber allows the fiber to be recessed inside the shield tube, providing further protection from discharge by-products.

Optical pseudospark switch

Semi-insulating gallium arsenide wafers manufactured with varying silicon nsity shallow donors are copper compensated by heating to temperature of at least 550.degree. C. to thermally diffuse the copper into the wafers and thereby provide deep copper acceptors in the wafer. Higher annealing temperatures are employed for higher concentrations of silicon in the wafers and the thermal diffusion is accomplished in the presence of copper, and in some instances, in the presence of varying quantities of arsenic. The copper compensated, silicon doped, gallium arsenide wafers obtained have the electrical property characteristic capability of being used as photoconductive switching components. In one aspect of the invention the silicon doped gallium arsenide wafer is sealed in a quartz ampoule in the presence of solid copper and solid arsenic and heated to the annealing temperature. In another aspect of the invention, the copper and arsenic are flowed as vapors over the silicon doped gallium arsenide wafer disposed in a reaction tube within a diffusion furnace, while the wafer is heated to the annealing temperature.

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King George, VA, United States of America

David C Stoudt