Monte Carlo Simulation of Terahertz Radiation Waveform from SI-GaAs Photoconductive Antennas

A self-consistent Monte Carlo approach is used to simulate the time resolved terahertz radiation from Si-GaAs photoconductive antenna. An adjustable energy and width of fs laser pulse is applied to illuminate Si-GaAs-based photoconductive antennas. The THz wave profile by simulation is similar to THz radiation waveform from experiment. We analyzed carrier dynamics in photoconductive antenna, and interpreted the mechanism that the width of emitted THz pulse was much wider than the pump pulse. And the mechanism that THz bipolar waveform emitted from Si-GaAs-based photoconductor trigged by high energy optical pulse at lower biased voltage was studied.