Improvement of temporal contrast for ultrashort laser pulses by cross-polarized wave generation

Temporal contrast is a key factor influencing the performance of high-field physics experiments for ultraintense and ultrashort laser systems. The purpose of this paper is to improve the temporal contrast for ultraintense and ultrashort pulses in a laser system by cross-polarized wave (XPW) generation, a new method developed recently to enhance the temporal contrast effectively. Experiments were carried out to study the XPW generation efficiency and the enhancement of temporal contrast at the SILEX-I laser facility with a wavelength of 800 nm. The results show that the relationships between the efficiency of cross-polarized wave generation and crystal orientation/input intensity are in good agreement with theoretical predictions. Both the prepulse and the amplified spontaneous emission (ASE) pedestal are suppressed significantly and the temporal contrast is improved by two orders of magnitude by the method. With the amplification of the temporally cleaner pulses in the future, great opportunities will be created for high-field physics experiments at the laser facility.