交叉偏振滤波技术提高飞秒超强激光信噪比的研究

Enhancement of contrast ratio in chirped pulse amplified laser system by cross-polarized wave generation

对交叉偏振波滤波技术理论分析的基础上,在"极光-Ⅲ"装置中采用该技术进行了钛宝石飞秒放大激光脉冲对比度提高的实验研究,不仅显著的抑制了纳秒范围内再生放大器产生的预脉冲,而且也将皮秒范围内的信噪比由10-5提高到了10-7,实验测得基波到交叉偏振波的转化效率大于10%.研究表明,该技术可以有效地提高飞秒超强激光的信噪比。

This paper reports our experimental research on the laser contrast ratio enhancement in the XL-Ⅲ（eXtreme Light Ⅲ） facility with the technology of cross-polarized wave（XPW） generation.Based on the theoretical analysis of the relerant principles,we introduced an XPW filter in the facility,which was upgraded with a double chirped pulse amplification（DCPA） scheme.Under optimized system design and alignment,we measured the conversion efficiency from fundamental wave to cross-polarized wave to be higher than 10%.The pre-pulses in nanosecond scale were deeply suppressed and the contrast ratio in picosecond scale was enhanced from 10-5 to 10-7.Our results show the XPW generation provides an effective technique to improve the contrast ratio of a Chirped-pulse amplification laser system,which is a key issue in ultrahigh intensity laser-matter researches.