VECSEL热焦距测量以及角度调谐研究  

VECSEL Thermal Focus Length Measurement and Angle Tuning Research

作　　者：高勇喜 郭洁[1] 王巍 佟存柱[3] 梁晓燕[1] Gao Yongxi;Guo Jie;Wang Wei;Tong Cunzhu;Liang Xiaoyan(State Key Laboratory of High Field Laser Physics,Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,Shanghai 201800,China;Center of Materials Science and Optoelectronics Engineering,University of Chinese Academy of Sciences,Beijing 100049,China;State Key Laboratory of Luminescence and Applications,Changchun Institute of Optics,Fine Mechanics and Physics,Chinese Academy of Sciences,Changchun,Jilin 130033,China)

机构地区：[1]中国科学院上海光学精密机械研究所强场激光物理国家重点实验室,上海201800 [2]中国科学院大学材料与光电研究中心,北京100049 [3]中国科学院长春光学精密机械与物理研究所发光学及应用国家重点实验室,吉林长春130033

出　　处：《中国激光》2021年第5期243-249,共7页Chinese Journal of Lasers

基　　金：国家重点研发计划(2017YFB0405202)。

摘　　要：为了使半导体激光器输出高功率、高光束质量的激光,垂直外腔面发射激光器(VECSEL)应运而生。本文通过对激光器谐振腔的稳定条件进行计算,并结合实验估算出VECSEL中增益芯片的热透镜在泵浦功率为31.3 W时的热焦距在45.7 mm到53.6 mm之间。实验过程中观测到增益芯片的荧光光谱随观测角度变化的现象,并提出一种通过观测增益芯片在不同角度下的荧光光谱来直接估算VECSEL的调谐范围的方法,用所提方法测得增益芯片调谐范围为995~1030 nm。Objective The invention of semiconductor lasers has brought about a huge impetus to the laser industry.Traditional edge-emitting lasers can work with high efficiency and high average power,but the poor beam quality limits their widespread adoption.The invention of vertical cavity surface emitting lasers(VCSELs)improved the output of a semiconductor laser to a circular spot but with limited output power.Subsequently,vertical external cavity surface emitting lasers(VECSELs)emerged featuring a smaller divergence angle.Still,the power scaling capability and beam quality optimization could not be achieved at the same time due to the inhomogeneous electric current pump.Next came the optically pumped VECSELs.For conventional lasers,pumped laser crystals usually have a thermal lens effect.The range of focal length of thermal lens determines the scope of the stable area when the laser is operating.The gain chip of the vertical cavity surface emitting laser is a semiconductor material,so the focal length of the thermal lens cannot be directly calculated by the crystal thermal lens focal length formula.To evaluate the thermal lens effect of the gain chip,we estimate the thermal focal length of the gain chip.In addition,the tunable output range is an important parameter to characterize the output properties of the laser.In this article,we also propose a method for estimating the angle tuning range of the VECSEL by directly measuring the angle-dependent characteristics of the fluorescence spectrum of the gain chip.Furthermore,we conducted an angle tuning experiment to verify this method.Methods To measure the thermal focal length of the gain chip,we use the stability conditions of the laser cavity to determine the thermal focal length of the gain chip.During the experiment,we ensure that the thermal rollover phenomenon does not occur and the length of the resonator is fixed.The thermal focal length of the gain chip gradually decreases with increasing pump power until the active resonator meets the stability conditions,and the

关 键 词：激光器 垂直外腔面发射激光器(VECSEL) 热焦距 角度调谐 荧光光谱 

分 类 号：O436[机械工程—光学工程]