说明：  激光光束质量M2因子测量：在激光光路不同位置测量激光光斑直径，将数据导入本程序，即可得到拟合曲线以及一系列激光参数。
(The laser beam quality measurement: Detect the laser beam diameters at different distances in the optical path and then input these data into this program, you can get fitting curves and other laser parameters.)