基于空谱干涉扫描法测量超宽带激光时空耦合特性

Measurement of spatiotemporal coupling characteristics of ultra broadband pulsed laser beam based on spatial spectrum interferometric scanning

大口径超高峰值功率激光装置中展宽器、压缩器、透镜等光学元件会导致不同空间位置的脉冲波形及延时各有不同,称为“时空耦合效应”.常规的测量手段仅能反映激光近场的局部时间特性,本文设计并验证了一种基于空谱干涉线扫描的时空特性测试方案:采用空谱干涉方法单次测量可获得一个空间维度上的时空耦合特性,通过沿另一空间维度扫描,即可获得完整的近场时空耦合特征.利用该方法实验测量了劈板引入的角色散以及近场不同空间位置处的脉冲波形、脉冲前沿、脉冲宽度等信息,与理论计算结果符合得较好,说明该方法能够有效地测量超宽带激光的时空耦合特性.

Optical elements such as stretcher,compressor and thick lenses will lead to spatially-dependent temporal properties of a large aperture laser pulse,which is called spatiotemporal coupling(STC).Beyond pure temporal characterization measurement,a measure of spatiotemporal coupling distortion based on spatial-spectral interference is proposed in this study.Full one-dimensional spatiotemporal coupling characteristics can be obtained in a single-shot measurement,and the complete spatiotemporal coupling characteristics in the near field can be obtained by scanning along another spatial dimension.The spatiotemporal coupling characteristics introduced by the wedge glasses are measured,and the experimental results accord well with the theoretical results.