用干涉自相关包络宽度测量超短激光脉冲啁啾

Estimation chirp in ultrashort laser pulses using interferometric autocorrelation envelope width

为了测量超短激光脉冲啁啾值,提出了一种用2次干涉自相关包络宽度测量啁啾值的简单方法。利用2次干涉自相关包络宽度对啁啾有很高的灵敏度、含有不同啁啾量的超短激光脉冲有不同的包络宽度的特性,通过对高斯型强度分布的线性、平方及立方啁啾的干涉自相关包络函数进行了理论分析,得到包络宽度与啁啾量值之间的对应关系。采用干涉自相关2次谐波检测系统对加浓染料激光器输出的含有啁啾的脉冲进行测量,其干涉自相关包络宽度为1.15,被测超短激光脉冲啁啾为1.0。结果表明,根据含有啁啾的干涉自相关曲线两翼的特征,可判断啁啾阶数,再根据包络宽度与啁啾值的对应关系,可估定啁啾量值;用干涉自相关包络宽度能容易地测量超短激光脉冲的啁啾量值。

A simple method was presented to determine various higher order chirps in ultrashort laser pulses based on interferometrle autoeorrelation （IAC） envelope width. This method is highly sensitive to chirp, dependence of envelope width of IAC on different magnitude of the chirp and its order. Through the Gaussian intensity of the linear chirp, square and cubic chirp pulses were analyzed and numerical calculated, IAC envelope width as a functions of the normalized mean chirp for different orders of chirp were obtained. The theoretical analysis was supported by experimental envelope width, IAC signals obtained using laser chirped pulses from a CW dye ring laser in the colliding pulse mode （CPM） locked regime. According to the characteristics of IAC envelope, the square chirp pulse was determined, the envelope width was measured 1.15 and the chirped ultrashort laser pulse was measured 1.0. The results show that the order of chirp can be determined according to the chirp characteristics of the two wings of IAC envelope and that the value of the chirp can be estimated according to its dependence on the envelope width. Chirp of ultrashort laser pulses can be determined easily based on the IAC envelope width.