Time-resolved study of intense terahertz pulses generated by a large-aperture photoconductive antenna

Saturation behavior of intense terahertz radiation pulses emitted by a large-aperture photoconductive antenna was studied by observing the waveforms of the generated terahertz pulse using the electrooptic sampling method. A peak terahertz field up to 5.7 kV/cm was observed. By increasing the pump pulse fluence, saturation of the peak terahertz field, shift of the peak appearance time and narrowing of the terahertz pulse were observed. These experimental results were found to be qualitatively consistent with the results of simulation based on the current surge model.