中国激光, 2008, 35 (s1): 98, 网络出版: 2008-04-21
一种基于散焦光栅的光束质量M2因子实时测量技术
Real-Time Measurement of Beam Quality Factor M2 Based on Defocus Gratings
测量 激光光束质量 M2因子测量 散焦光栅 多平面成像 measurement laser beam quality measurement of the factor M2 defocus grating multiplane imaging
摘要
设计出相位型正交散焦光栅,实现了一种新的光束质量M2因子实时测量技术。将散焦光栅和短焦透镜密接使用,透镜提供主要的聚焦能力,散焦光栅产生9个光轴,且在每个光轴上对焦距进行微调,使之具有不同的等效焦距,这样利用单一的CCD就可以在透镜焦平面上同时测量待测光束9个不同位置处的光强分布图样。利用二阶矩的方法计算束宽,经双曲线拟合得到光束的M2因子。对He-Ne激光器的输出光束进行了测量,得到其光束质量因子M2=5.775,与传统测量方法得到的结果相比,误差为5.1%。
Abstract
Crossed phase defocus gratings are designed and a new technique for real-time measurement of beam quality factor M2 is achieved. We can get the beam spots at 9 various positions to be measured simultaneously by using the defocus gratings closely connecting with a short-focal-length lens. The lens provides the majority of the focusing power and the grating provides 9 separate optical axes and effectively modifies the focal length of each axis. The value of M2 is determined by calculating the beam diameters using the second moment method and curve-fitting. A He-Ne laser beam is measured by using the gratings designed and a M2 value of 5.775 is achieved. Compared with a conventional measurement, the error is 5.1%.
耿义峰, 许晓军, 习锋杰. 一种基于散焦光栅的光束质量M2因子实时测量技术[J]. 中国激光, 2008, 35(s1): 98. Geng Yifeng, Xu Xiaojun, Xi Fengjie. Real-Time Measurement of Beam Quality Factor M2 Based on Defocus Gratings[J]. Chinese Journal of Lasers, 2008, 35(s1): 98.