A photoconductive switch-arrayed antenna with a chemical vapor-deposited diamond film was developed to generate high-power terahertz (THz) radiation. With this device, an electric field stress of 2 × 106 V/cm can be applied to photoconductive gaps because of the high breakdown threshold of diamond and the overcoated gap structure for the prevention of surface flashover. This level of field stress can alleviate the current problem of saturation in THz emission by use of a photoconductive antenna. The device consists of more than two thousand 20 µm × 2.8 mm emitters. In an experiment using an ultrashort pulse Kr*F laser, we obtained an energy density of 10 µJ/cm2 on the emitter surface at E = 105 V/cm. This density was larger than that of the current large-aperture antenna. There was no severe saturation in photoconductive current up to E = 106 V/cm, and a focused intensity of 200 MW/cm2 can be expected.
© 2001 Optical Society of AmericaPDF Article