Resonant-optical-cavity photoconductive switch with 0.5% conversion efficiency and 1.0 W peak power

We report a new photoconductive switch having an average output power of 44 microW, an instantaneous bandwidth of approximately 300 GHz, an output pulse width of approximately 2.2 ps, a peak output power of approximately 1.0 W, and an optical-to-electrical conversion efficiency of approximately 0.5% when pumped by a palm-sized mode-locked free-space laser at lambda=780.6 nm with an average power of 8.7 mW and an optical pulse width of approximately -230 fs. The switch is made from an ErAs:GaAs epitaxial layer inside a resonant optical cavity and coupled to a planar three-turn square spiral antenna.