Sub-terahertz microsecond optically controlled switch with GaAs active element beyond the photoelectric threshold

We study an unusual working regime of a recently developed sub-terahertz microwave cavity-based switch. The resonator cavity includes a semiconductor plate which is illuminated by laser emission beyond the photoelectric threshold. Despite a significant change to the conventional process of photoelectric effect we have found that the switch works. Typical switching performance rate is about 1 μs for the regime. A process of carrier density relaxation beyond the photoelectric threshold is discussed. An idea of diagnostic method for the semiconductor's quality is proposed.