激光二极管端泵方形Tm:YAG复合晶体的热效应  

Thermal effect of laser diode end pump square Tm:YAG composite crystal

作　　者：任嘉欣 李隆[1,2] 李昕阳 杨恒鑫 纪玉潇 张春玲 Ren Jiaxin;Li Long;Li Xinyang;Yang Hengxin;Ji Yuxiao;Zhang Chunling(Faculty of Science,Xi'an University of Architecture&Technology,Xi'an 710055,China;Institute for Applied Physics,Xi'an University of Architecture&Technology,Xi'an 710055,China)

机构地区：[1]西安建筑科技大学理学院,陕西西安710055 [2]西安建筑科技大学应用物理研究所,陕西西安710055

出　　处：《红外与激光工程》2024年第3期129-138,共10页Infrared and Laser Engineering

基　　金：国家自然科学基金项目(11705136)。

摘　　要：为了有效解决激光二极管端面泵浦激光晶体引起的热效应问题,引入复合晶体的概念,通过两种复合晶体模型(即单端键合和双端键合)来降低激光晶体的热效应。根据激光二极管端面泵浦激光晶体工作特点,建立端面泵浦方形Tm:YAG复合晶体热模型,利用热传导理论,用有限元分析法对复合晶体的温度场、热应力场和形变量进行了数值计算,分析了单端/双端键合方式、未掺杂晶体长度、增益晶体长度对方形复合晶体内部温度场及形变量的影响。结果表明,平衡状态下,激光二极管泵浦功率为30 W、泵浦光斑半径为400μm时,YAG晶体厚度c_(1)为1 mm,增益晶体厚度c_(2)为1.5 mm,方形单端键合和双端键合的Tm:YAG复合晶体内部最大温升分别为81.2、77.9℃;内部最大应力分别为146、104 MPa;热形变量为0.468、0.172μm。可见,复合晶体能有效缓解晶体的温升和热形变,且双端键合的方式降低晶体热效应的效果更好。当增益晶体厚度为2.6 mm以上时,两种键合方式对复合晶体内部最大温升的影响基本保持一致。该研究为方形Tm:YAG复合晶体的增益晶体厚度、未掺杂晶体厚度的选择提供了参考依据,也为实现Tm:YAG激光器高功率输出目标提供了理论指导。Objective The mid-infrared 2μm solid-state laser has unique characteristics in terms of output wavelength:it is in the atmospheric window,the absorption band of water and the human eye safety zone.Based on these special properties,it can be widely used in laser imaging radar,doppler coherent wind radar,differential absorption radar and other laser sources used to measure the concentration and temperature changes of the earth's atmosphere.In addition,the 2μm band laser can also be used as a pump source for optical parametric oscillators to achieve longer wavelength infrared laser output.With the deepening of research on 2μm solid-state lasers,thermal effect has become a major problem limiting laser output power and beam quality improvement,so it has attracted much attention.During the operation of solid-state lasers,the heat generation is due to quantum deficit,energy conversion between the lower laser level and the ground state,and laser quenching,which leads to uneven temperature distribution inside the laser crystal,resulting in thermal lensing effect.However,by using bonding technology to bond YAG crystals with Tm:YAG crystals to form composite crystals as the working material of lasers,the influence of thermal effect can be effectively reduced.Lasers using composite crystals have advantages such as high reliability,peak power and excellent spot quality Methods In this paper,the thermal effect of laser crystals is reduced by introducing two composite crystal models,namely single-ended bond and double-ended bond.By analyzing the working characteristics of continuous LD end-pumped square composite Tm:YAG crystal,a heat source heat model of laser crystal(Square Tm:YAG crystal model and its heat sink experimental device structure schematic diagram as shown in Fig.2)is constructed.Considering the boundary conditions of thermal convection between the crystal rod end face and air and the surrounding constant temperature,the finite element analysis method is used.The thermal effect of laser diode end pump square co

关 键 词：激光二极管 温度场 热形变 复合晶体 单端键合 双端键合 

分 类 号：TN248.1[电子电信—物理电子学]