High power C-Doped GaN photoconductive THz emitter

We report for the first time a carbon-doped gallium nitride based large aperture photoconductive switch grown on the sapphire substrate to generate high power sub-THz waves. The estimated THz wave energy was about 1.5 pJ/pulse when this device was pumped by a 266 nm wavelength femtosecond laser operating at 1 kHz pulse rate with the average power of 20 mW under the dc bias voltage of 110 V. The terahertz time domain spectroscopy was performed using a low temperature grown gallium arsenide photoconductive switch detector and the frequency spectrum was found to be in the 0.1-0.2 THz regime.