Influence of femtosecond laser pulse width on performance of terahertz time domain spectrometer

In this paper, a series of experiments on dispersion compensation in terahertz time-domain spectrometers are performed. The Influence of femtosecond laser pulse width on the performance of terahertz time-domain spectrometers is systematically studied. A terahertz time-domain spectroscopy system was constructed using fiber coupled photoconductive antennas. Through the adjustment of the grating spacing and the replacement of different lengths of fiber cable, the laser pulse width acting on the antenna was multiplexed from 130fs to 2.46ps, and the performance of the terahertz time domain spectroscopy system under different pulse widths was tested. The experimental results show that, with the increase of the femtosecond laser pulse width, the signal intensity of the terahertz time domain waveform and the high frequency part of the terahertz spectrum decrease significantly. Quantitative comparative analysis was performed using the average signal-to-noise ratio, validating the necessity of using dispersion compensation and femtosecond laser pulse width testing in the terahertz time-domain spectroscopy system.