Design and development of high-power terahertz radiation emitter with diamond photoconductive switch

A photoconductive switch arrayed antenna with a chemical vapor deposited (CVD) diamond film was designed and developed for generating high-power terahertz (THz). In CVD dimoand, an electric field stress of 2/spl times/10/sup 6/ V/cm can be applied to the gaps because of the high breakdown threshold properties and the gap structure for preventing surface flashover. This level of field stress can alleviate the present problem of saturation in THz emission using a photoconductive antenna. In demonstration experiment using an ultrashort pulse Kr*F laser, an energy density of 10 /spl mu/J/cm/sup 2/ on the emitter surface was obtained at E=10/sup 5/ V/crn. This density was larger than that of the present large aperture antenna. The 2-inch´s aperture device, which was consisted of more than two thousand 20 /spl mu/m /spl times/2.8 mm emitter arrays, were developed. There was no severe saturation in photoconductive current up to E=10/sup 6/ V/cm, and a focused intensity of 200 MW/cm/sup 2/ can be expected.