Milliwatt THz average output power from a photoconductive switch

We report the design and measurement details of a new GaAs-based THz photoconductive switch with an average power level in excess of 1 mW and peak power up to 33 W when pumped by a 780-nm, subpicosecond pulse train from a frequency-doubled 1.55-nm fiber mode-locked laser. The power was measured with a thermopile detector calibrated for THz operation and having very high saturation level. The median power frequency of the present photoconductive switch is estimated to be 400 GHz.