固体激光器涡旋光束产生实验系统设计与实现  

Design and implementation of an experimental system for the generation of vortex beams using a solid-state laser

作　　者：连天虹[1] 寇科 刘丽娟[1] 王萌[1] LIAN Tianhong;KOU Ke;LIU Lijuan;WANG Meng(School of Mechanical and Precision Instrument Engineering,Xi'an University of Technology,Xi'an 710048,China)

机构地区：[1]西安理工大学机械与精密仪器工程学院,陕西西安710048

出　　处：《实验技术与管理》2024年第4期39-45,共7页Experimental Technology and Management

基　　金：国家自然科学基金青年项目(61805196)。

摘　　要：高质量的涡旋光束在量子信息、激光雷达、激光通信等领域有着广泛的应用前景。为了用固体激光器直接产生涡旋光束,该文基于谐振腔模式与激光介质作用的速率方程,阐述了在二极管端面泵浦固体激光器中通过环形光泵浦产生拉盖尔-高斯涡旋光的原理。设计了环形光泵浦固体激光器产生涡旋光的实验方案并搭建了实验系统。实验产生了角向阶次为1阶、2阶的涡旋光束,相位涡旋手性可通过微调谐振腔输出镜调节。该实验能够使学生利用固体激光器直接产生涡旋光束并观察涡旋光束的相位特性,有助于学生加深对激光谐振腔模式理论及涡旋光束相位特性的理解,为相关专业学生的课程教学提供有力支撑。[Objective]Optical vortex beams have wide application prospects in quantum information,light detection and ranging,and optical communication.Vortex beam generation is the first and key part of the problem yet to be solved for these applications.However,generating vortex beams with high beam quality remains a challenge.Because the most common vortex beams,Laguerre–Gaussian beams,are the eigenmodes of the laser cavity,generating vortex beams directly using lasers has the advantages of high purity and high power compared with the extra-cavity method.To generate vortex beams directly using diode end-pumped solid-state lasers,this study aims to analyze the generation principle of vortex beams in solid-state lasers.This principle is based on the rate equations of population inversion and cavity photon density.Then,an experimental vortex laser system is designed,and the experimental platform is built.[Methods]This study establishes space-dependent rate equations for population inversion in the laser medium and photon density in the laser cavity.By solving the rate equations,we obtain the threshold pump power of the laser modes in a steady state.The pump power is dependent on the overlapping integral of the normalized pump intensity and the normalized photon density in the laser cavity.Then,we calculate the overlapping integral of the flattop ring pump beam and the Laguerre–Gaussian modes.The overlapping integral and the mode threshold change with the change in the radius of the pump beam.By adjusting the radius of the pump beam,the cavity modes can be selectively exited,and a specific vortex beam can be generated.According to this principle,an experimental scheme for the diode end-pumped solid-state vortex laser is designed.The collimated fiber-coupled output beam of the diode is tailored to a ring distribution using a circular opaque disk of 2 mm diameter.The ring pump beam is focused into the Nd:YAG laser crystal,which has a 2 mm thickness and 10 mm diameter.The radius of the ring pump beam in the laser crystal ca

关 键 词：固体激光器 高阶模式 涡旋光束 相位特性 

分 类 号：TN248.1[电子电信—物理电子学]