超短超强激光焦斑参数的精确测量是深入开展精密物理实验的前提。在SILEX-Ⅰ激光装置上, 采用光学成像法和穿孔法测量了μJ级能量下的激光焦斑特性, 采用光学成像方法得到了激光主瓣大小及能量集中度信息, 通过穿孔法得到了激光能量透过率与不同大小孔径的关系曲线, 并对两种方法得到的测量结果进行了比对研究。研究结果表明, 光学焦斑测量法和穿孔法都可以比较准确地反映激光焦斑的能量分布情况, 得到的能量分布偏差小于10%。

For the interaction experiments between ultra-intense laser and targets, characterizing the laser focusing spot is very important. Two different methods were adopted on SILEX-Ⅰ Ti:sappire femtosecond laser system. One is directly imaging the laser spot on 16bit CCD, another is measuring the transmitting energy behind a pinhole which was exactly positioned on the laser focusing spot. Both methods can give the correct distribution of the focal spot with less than error 10%.