砷化镓光导天线太赫兹发射器场筛选效应的时间特性

he field screening effects in small-size GaAs photoconductive antenna are investigated via the well-known pump and probe terahertz (THz) generation technique. The peak amplitude of the THz pulses excited by the probe laser pulse as a function of the pump-probe time delay is measured. An equivalent-circuit model is used to simulate the experimental data. Based on the good agreement between the simulation and experiment, the time behavior of the radiation and space-charge fields is simulated. The results show that the space-charge screening dominantly determines the device response in the whole time, while the radiation filed screening plays a key role in initial time which strongly affects the peak THz field. The parameter analysis is performed, which may be valuable on the optimum design for the antenna as a THz emitter.