高功率激光束光束质量的数值评价方法

Mathematical Method of Estimation of Beam Quality of High Power Lasers

为估计１０１２Ｗ高功率激光器的光束质量，本文采用最小二乘法对已重构的波前曲面进行球面拟合，得到相对应的无波像差参考波前。利用无波像差参考波前的曲率半径计算出高功率激光光束的衍射角，由有畸变波前与无波像差参考波前的波像差估算出激光束的Ｓｔｒｅｈｌ比。

In order to appreciate the beam quality of 10 12 W high power laser,the spherical surface fitting of reconstructed wavefront was done with least square approximation,and it gave the reference wavefront with no distortion.The diffraction angle of beam of high power laser was calculated with radius of curvature of reference wavefront.The Strehl ratio of the beam can be estimated with the wave aberration between distorted wavefront and reference wavefront.Those quantitative results which appreciated the beam qualities of high power laser showed that the angles of divergence of laser beams were about 10 -4 rad in order of magnitude,and that Strehl ratios were about 10 -17 in order of magnitude,because there were the thermal relaxation processes in the experiments.