Maximizing THz amplitude for improved pulse parameters and high power applications

A THz generating, low temperature grown semi-Insulating Gallium Arsenide photo conductive semiconductor switch was analyzed for optimum pulse amplitude for high power applications. The switching voltage which controls the substrate conditions for the given geometry was determined by monitoring the conditions in the trap-filled substrate region of the switch during the charging state. Trap occupancy, current flow lines, and the electric field were the major parameters monitored. The switch was illuminated for 350 fs with a 0.78 μm beam, and a power density of 50 Mw/cm². Results show that the switch produces a central frequency of 1.75 Terahertz, with a pulse amplitude of approximately 0.22 A at an optimum bias voltage of 1100 Volts. The FWHM of the generated pulse 0.4 ps, and the rise time is 0.275 ps.