激光二极管端泵Yb:YAG晶体的温度场及应力场  

Temperature field and stress field of LD end-pumped Yb:YAG crystal

作　　者：李昕阳 李隆[1,2] 任嘉欣 贺政隆 石镨 宁江浩 张春玲 Li Xinyang;Li Long;Ren Jiaxin;He Zhenglong;Shi Pu;Ning Jianghao;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110-117,共8页Infrared and Laser Engineering

基　　金：国家自然科学基金项目(11705136)。

摘　　要：为了解决激光二极管端面泵浦Yb:YAG晶体引起的热效应问题,通过对晶体工作特点的分析,建立了周边冷却恒温、端面与空气存在热交换的有限元热模型。利用泊松方程,对Yb:YAG晶体的温度场、热应力场、热形变场和热透镜焦距进行了数值计算,并定量分析了激光二极管泵浦光的高斯阶次、光斑半径和泵浦功率对激光晶体温度场的影响。研究结果表明:若激光二极管泵浦功率为50 W,耦合到泵浦面的光斑半径为400μm时,晶体尺寸为3 mm×3 mm×4 mm、掺杂浓度为5.0 at.%的Yb:YAG晶体端面的最高温升为59.2 K,最大热形变量为0.64567μm,晶体内稳定时最大应力为2.380×108 N/m^(2),热透镜焦距为19.99 mm,该条件下激光器可正常运行。研究结果为全固态Yb:YAG激光器的设计提供了理论依据。Objective Laser is a device that can emit high energy radiation,and its excellent characteristics make it to be widely used and paid attention to by researchers in various fields.Its most important part is the laser crystal.During the operation of the laser,the crystal will generate a lot of heat inside the crystal because of the crystal thermal effect such as quantum deficit,and cause the gradient distribution of stress and crystal deformation,which seriously affects the beam quality of the laser.Therefore,studying the thermal effect of crystals is an important step to design and manufacture lasers with high beam quality.In this paper,through the simulation of the working state of the laser,the monitoring of the temperature field and stress field inside the crystal is tested,so as to provide data and theoretical support for better laser design.Methods In order to simulate the working state of the laser and monitor the temperature field and stress field,the model conditions are simplified based on the actual situation.The temperature distribution in the crystal is analyzed by the Poisson equation in the thermodynamic theory,and the stress distribution in the incident direction is analyzed by the mechanical theory.Then the geometric model is established by finite element analysis,and the theoretical model close to the working state of the crystal is obtained by combining them.The boundary conditions around the crystal are analyzed and the physical field constraints are given to the model.Finally,the control variable method is used to analyze the variables in the system.Results and Discussions The initial conditions are as follows.The model size is 3 mm×3 mm×4 mm,doping concentration is 5.0 at.%,absorption coefficient of 940 nm pump light is 5.6 cm−1,thermal conductivity is 0.13 W·cm^(−1)·K^(−1),Gauss order is 1,cooling temperature T0 is 291 K.The coefficient of thermal expansion is 7.8×10^(−6)K^(−1).When the laser pump power is 50 W and the spot radius of the pump surface is 400μm,the maximum tempe

关 键 词：热效应 温度场 有限元分析 YB:YAG激光器 端面泵浦 

分 类 号：TN248.1[电子电信—物理电子学]