Optically generated THz beams from metal/GaAs interfaces

Free space generation and propagation of electromagnetic pulses at THz frequencies is a fast growing sub-field in the photonics and optoelectronics community. Currently there are two general techniques utilizing ultrafast laser pulses to generate THz beams from semiconductors: photoconduction and optical rectification. The photoconductive method uses high-speed photoconductors as transient current sources for radiating antennas, whereas optical rectification uses electro-optic crystals as nonlinear media for difference-frequency-generation. In this paper we report on further studies of laser induced THz beams form metal/GaAs interfaces.