刀口法测量拉盖尔-高斯涡旋光斑的理论与实验研究  

Theoretical and Experimental Study on the Measurement of Laguerre-Gaussian Vortex Spot Size Using Knife-Edge Method

作　　者：马靖博 李鹏 周子恒 韩现伟 吴振坤 戴树玺[1,2] 顾玉宗 Ma Jingbo;Li Peng;Zhou Ziheng;Han Xianwei;Wu Zhenkun;Dai Shuxi;Gu Yuzong(Research Center for Physics of 2D Opto-Electronic Materials and Devices,School of Physics and Electronics,Henan University,Kaifeng,Henan 475004,China;International Joint Research Laboratory of New Energy Materials and Devices of Henan Province,Kaifeng,Henan 475004,China;Department of Measurement&Control Technology and Instrument,School of Physics and Electronics,Henan University,Kaifeng,Henan 475004,China)

机构地区：[1]河南大学物理与电子学院二维光电材料与器件物理研究中心,河南开封475004 [2]河南省新能源材料与器件国际联合实验室,河南开封475004 [3]河南大学物理与电子学院测控技术与仪器系,河南开封475004

出　　处：《激光与光电子学进展》2021年第19期189-198,共10页Laser & Optoelectronics Progress

基　　金：国家自然科学基金(61875053,61805068,12104131);河南省科技发展计划项目(202300410072,181100211300);河南省教育厅科学技术研究重点项目(18A140002)。

摘　　要：拉盖尔-高斯(LG_(0l))涡旋光束携带光轨道角动量,提供了额外复用自由度,可以极大提高光通信容量,实现该涡旋光束光斑半径的精确测量对其应用具有重要意义。刀口法由于廉价、方便、精度高、适用于较大功率的测量等优势,是测量光斑尺寸及束腰尺寸的理想方法。然而,以往刀口法的研究主要集中在基横模高斯光束上,尚缺少关于刀口法对LG_(0l)涡旋光斑的测量研究。本文对基于刀口法的LG_(0l)涡旋光斑尺寸测量进行了详细地理论分析和实验研究。理论分析中给出了刀口法测量LG_(0l)涡旋光束的原理;实验上将螺旋相位板对基模高斯光束调制后产生的光束当作LG_(0l)涡旋光束的近似,并采用刀口法测量了该LG_(0l)(l=0,1和2)涡旋光的光斑;借助Mathematica程序数值拟合了实验测量的横向光场强度分布结果,得到了不同LG_(0l)涡旋光束的光斑半径。根据光斑半径的特点可得出:经低涡旋阶数的螺旋相位板调制之后,基模高斯光束可变为相应涡旋阶数的LG_(0l)涡旋光束,变换前后光斑半径基本保持不变。Laguerre-Gaussian(LG;)vortex beam carries optical angular momentum and provides additional multiplexing degrees of freedom,which significantly improve the optical communication capacity.The accurate measurement of the spot size of the LG;vortex beam is of great significance owing to its application.The knife-edge method is an ideal method for measuring the spot size and waist radius of the beam for its advantages of low cost,convenience,high precision,and suitability for high-power measurement.However,previous studies on this method focused on the fundamental transverse mode Gaussian beam.Moreover,to the best of our knowledge,there is no research on the measurement of the LG;vortex spot using the knife-edge method.In this study,the measurement of the spot size of the LG;vortex beam based on the knife-edge method is investigated theoretically and experimentally.In the theoretical analysis,the principle for measuring the LG;vortex beam is presented.In the experiment,the LG;vortex beam is generated by modulating the fundamental Gaussian beam using spiral phase plate(SPP).The vortex beam spot is measured using the knife-edge method.The spot radii of LG;vortex beams(l=0,1,and 2)are obtained after fitting the intensity distribution of the transverse field using the Mathematica program.According to the characteristics of the spot radii,we conclude that the spot radius remains unchanged during the transformation from the fundamental Gaussian beam to the LG;vortex beam using the SPP of lower order.

关 键 词：测量 LG 涡旋光束 刀口法 光斑半径 Mathematica程序 

分 类 号：O436.1[机械工程—光学工程]