为得到近场光束强度分布对激光束光束质量的影响程度, 利用快速傅里叶变换算法对实验中测得的高能化学激光器产生的光束实例进行了计算。本次数据采集所用的激光器腔型为正支共焦非稳腔, 最终输出的光束为空心的方环形。利用 F因子对激光束近场强度均匀性进行了评估, 并使用光束质量因子茁值对一系列远场光斑的光束质量进行了评价。由计算结果可以得出, 在本次实验样本中近场强度分布对激光束的光束质量茁值影响在 1.2～1.4之间。

In order to know how the near field intensity distribution influences the beam quality, Fast Fourier transform method isused to calculate the near field intensity of the high power chemical laser. The cavity of the laser is confocal positive branch unstableresonator, so the beam is rectangular and hollow. Evaluating the uniformity of near field beam intensity by F value and evaluating thebeam quality of the far field profiles by beta value. It was shown that, the intensity factor of the near field beam would affect the茁 value of the far field quality, between 1.2～1.4.