Nonlinear Model of Photoconductive Antennas

The terahertz radiations generated through a slab of GaAs-based photoconductive antennas are calculated from the nonlinear model and measured by a time domain spectroscopy system. The calculated spectra for the different pulses are in agreement with our experimental observations. This consistency suggests that the description of the nonlinear model captures the basic features of this photoelectrical terahertz emission mechanism. Furthermore, 1/f background noise dominates the terahertz detection in our experiments when the frequency is larger than 3 THz.