High power terahertz radiation with diamond photoconductive antenna array

High power terahertz (THz) radiation was generated from a photoconductive diamond switch array for the first time. This device consisted of more than 2000 photoconductive gaps and a binary mask for spatial modulation of pumping laser. Due to-the high breakdown threshold of diamond and the over-coated gap structure for preventing surface flashover, high electric field strength (2/spl times/10/sup 6/ V/cm) can be applied on each gap with DC mode. A 10 nJ, 1.5 ps FWHM free propagating electromagnetic pulse was observed from 10 mm/sup 2/ effective emission area at E=10/sup 5/ V/cm. This radiation was focused on to 1.4 mm/spl phi/ spot with F/2 optics. As there was no severe saturation observed in photoconductive phenomena in CVD diamond up to 10/sup 6/ V/cm, the focusing intensity can be increased to GW/cm/sup 2/ level by increasing the applied electric field and the switching area.