基于平凸柱面镜的LIBS光束整形系统设计

Design of LIBS Beam Shaping System Based on Plano-Convex Cylindrical Mirror

为改善激光诱导击穿光谱(Laser-induced breakdown spectroscopy,LIBS)技术激光能量不均匀分布的问题,利用仿真软件对半径为12.5 mm的不同焦距型号的平凸柱面镜进行光路成像模拟,模拟显示满足激光器条件的最佳焦距为100 mm,在此基础上搭建基于LIBS光束的整形系统。实验表明,相比于无平凸柱面镜整形,样品中锶元素的焦斑光强均方差系数平均降低了41.91%,焦斑光强峰谷比系数平均降低了41.27%,而能量均匀度平均提高了17.23%,拟合决定系数由0.860提高到了0.914。结果显示,使用平凸柱面镜可提高光束能量的均匀性,验证了平凸柱面镜是激光光束整形的一种有效方法。

In order to improve the uneven distribution of laser energy in laser-induced breakdown spectroscopy(LIBS)technology,simulation software was used to simulate the optical path imaging of flat convex cylindrical mirrors with different focal lengths of 12.5 mm radius.The simulation showed that the optimal focal length meeting the laser conditions was 100 mm.On this basis,a shaping system based on LIBS beam was built.Compared with the non-convex mirror,the mean square error coefficient of focal spot light intensity for the strontium element in the sample decreased by an average of 41.91%,the peak-to-valley ratio of focal spot intensity decreased by an average of 41.27%,the energy uniformity increased by an average of 17.23%,and the coefficient of determination for the fitting increased from 0.860 to 0.914.The results show that the plano-convex cylindrical mirror can improve the uniformity of beam energy,proving that it is an effective method for laser beam shaping.