针对半导体激光二极管由束散角大(14°~46°)导致的激光功率密度在传播过程中不断衰减的问题, 提出了一种提高激光功率密度的光束整形方法。首先以X型柱面平凸透镜和Y型柱面平凸透镜对激光二极管输出光束慢轴和快轴方向进行准直, 然后通过一对平凸透镜组合进行扩束, 进一步提高光束平行度, 最后由单片平凸透镜将光束聚焦为高功率密度的光点。采用Light Tools软件仿真光路、优化光学元件参数, 对光学元件进行实际选型后安装并调试光束整形系统。测试结果表明: 半导体激光二极管输出光束的67%激光能量汇聚于直径1 mm圆内, 激光功率密度优于30 W/cm2。

To solve the problem that the power density of laser beam attenuated along the propagation direction, which was caused by large beam divergence angle (14°-46°) of semiconductor laser diode, a beam shaping optical system to improve power density was proposed. An X type planoconvex cylindrical lens and a Y type planoconvex cylindrical lens were selected to collimate the laser beam. Then, a pair of planoconvex spherical lenses were applied to improve the parallelism. Finally, a single planoconvex spherical lens focused the laser beam to a spot with high power density. The lenses were chosen and optimized through Light Tools simulation. A real beam shaping optical system was mounted and built. Test results show that 67% laser power is converged into a cycle with diameter of 1 mm, and the power density is over 30 W/cm2.