高功率叠阵二极管激光器光束整形

Beam reshape of high power laser diode stack

采用光线追迹法详细分析线阵二极管激光器经微球面柱透镜快轴准直后的光强变化情况,利用快轴准直微球面柱透镜的球差可调整输出激光光强分布的特性,得出了快轴准直输出发散角约5°时光强分布具有较好的平顶形式。根据叠阵二极管激光器输出光的特点,设计了由25个二极管激光器组成的叠阵二极管激光器的光束整形输出系统,该系统由快轴准直微透镜、快轴耦合透镜和慢轴耦合透镜组成,把需要泵浦的激光介质薄片设计在快轴耦合透镜的焦点上,并且在慢轴耦合透镜的成像面附近,得到了7mm×8mm的泵浦光斑,光强不均匀性约10%,输出效率达到85%。

Based on the ray tracing method the laser intensity distribution of single DL bar collimated with micro spherical cylindrical lens was analyzed in detail. We found that the intensity distribution of output laser have a better flat shape when the divergence angle is about 5°. A beam reshape system was designed for a 25-bar DL stack. The system includes microlens of fast axis collimating, coupling lens of fast axis and coupling lens of slow axis. The laser medium to be pumped was designed at the focus plane of fast axis coupling lens and close to the imaging plane of slow axis coupling lens. A 7 mm×8 mm pump beam was ob- tained with intensity uniformity of 90 %. The coupling efficiency of the beam reshaping system reached 85%.