Distortion reduction by introducing extra birefringence in intense terahertz time-domain spectroscopy system

Numerical and experimental demonstrations are presented to reduce the distortion induced by intense terahertz field in a cross-polarized terahertz time-domain spectroscopy system. A quarter-wave plate is used to increase the initial birefringence of the probe beam. With an optimized angle, the distortion can be removed effectively, while the signal-to-noise ratio of the system is also improved.