Electric field dependence of pulsed THz emission from photoconductive antennas

It has been postulated that terahertz (THz) generation in photoconductive emitters is associated with electric field transients between the electrodes of the device. This is supported by experimental measurements showing enhanced generation with near-anode device excitation. In this work we present a detailed analysis of the dependence of device performance on the position of laser excitation for two designs of photoconductive emitter. These results are compared to new investigations using the technique of electron beam induced current (EBIC) measurements. EBIC gives an alternative means of examining the electric field within a device, and the results are compared for the full range of applied device bias.