非链式脉冲DF激光器增益分布特性

为了研究非链式脉冲DF激光器的增益分布特性，在考虑谱线碰撞加宽和多普勒加宽对增益系数影响的基础上，运用变耦合率法给出了计算增益系数的简便公式。利用光阑移动扫描采样法，实验测量了不同输出镜透过率条件下DF激光器增益区横截面上各采样点的激光输出功率。对于每个采样点，计算得到两个独立的增益系数，其标准差差小于3%。激光平均增益系数为2.594 3 m-1，非输出损耗系数为1.243 5 m-1。对各采样点的增益系数进行二维插值，结果显示在激光增益区横截面上增益系数呈现中央高、边缘低的超高斯分布。研究成果可为非链式脉冲DF激光器谐振腔和电极结构设计提供依据，并可为该激光器的气体放电均匀性分析提供参考。

Investigation on gain distribution characteristic of non-chain pulsed DF laser

In order to investigate the gain distribution characteristic of non-chain pulsed DF laser, based on the influence of collision widen and Doppler widen of spectrum on gain coefficient, the simple equations were given to calculate the gain coefficient using the variable output coupling method. Under the conditions of different output mirror transmission, utilizing the method of moving iris to scan sample, the DF laser output power of every sampling position had been measured on the cross-section of gain medium. For arbitrary sampling position, two independent gain coefficients were calculated which standard deviation was less than 3%. Average gain coefficient of DF laser was 2.594 3 m-1 and the non-output loss coefficient was 1.243 5 m-1. For gain coefficients of each sampling position, two-dimensional interpolation algorithm had been used to obtain gain distribution on the cross-section of gain medium. The calculation showed that the gain coefficients submitted to supper-Gauss-Poisson distribution which was high in the central and low in the margin. The investigation could provide a guide to design resonator and electrode structure of non-chain pulse DF laser, and provide a reference to analyze the uniformity of gas discharge of this laser.