LD端面泵浦Er:Yb:glass/Co:MALO晶体热效应分析  

Thermal effect analysis of LD end-pumped Er:Yb:glass/Co:MALO crystal

作　　者：孙佳宁 王雨雷 张雨 齐瑶瑶 丁洁 颜秉政 白振旭 吕志伟 Sun Jianing;Wang Yulei;Zhang Yu;Qi Yaoyao;Ding Jie;Yan Bingzheng;Bai Zhenxu;Lv Zhiwei(Center for Advanced Laser Technology,Hebei University of Technology,Tianjin 300401,China;Hebei Key Laboratory of Advanced Laser Technology and Equipment,Tianjin 300401,China)

机构地区：[1]河北工业大学先进激光技术研究中心,天津300401 [2]河北省先进激光技术与装备重点实验室,天津300401

出　　处：《红外与激光工程》2023年第8期140-151,共12页Infrared and Laser Engineering

基　　金：国家自然科学基金项目(62075056,61927815);天津市自然科学基金项目(20JCZDJC00430);河北工业大学基本科研业务费项目(JBKYTD2201)。

摘　　要：为了减弱激光二极管端面泵浦固体激光器热效应的影响,提高激光谐振腔稳定性及改善激光器的输出特性,以激光二极管端面泵浦Er:Yb:glass/Co:MALO晶体为研究对象,采用有限元分析方法,并根据热传导理论对其进行多物理场耦合热效应分析,系统分析了非键合和键合晶体、泵浦中心波长、功率以及束腰半径对激光晶体的温度场、热应力场以及形变量的影响。结果表明:键合晶体中Co:MALO晶体不仅起到了被动调Q的作用,还起到了热沉的效果,可以有效改善晶体内部的温度分布、热应力和形变量。中心波长为940 nm的泵浦对晶体的穿透性远高于976 nm,采用940 nm的泵浦可以改善晶体的最高温度,但976 nm泵浦结构是扩散键合较安全的结构。由于增大泵浦功率会导致晶体单位面积功率密度分布的增加,热效应也会加剧,泵浦功率增大100 mW对应温度增加9 K,热应力增加1.5 MPa,热形变增加0.5μm。减小泵浦光束半径也会导致热效应的增加,但影响相较于功率不明显。理论分析结果可为激光二极管端面泵浦铒镱共掺磷酸盐玻璃1.5μm固体激光器减小热效应的合理优化设计提供数据理论支持。Objective The poor thermal conductivity of Er:Yb:glass leads to poor heat dissipation in the laser system and the increased thermal load leads to severe thermal effect,which limits the laser output of high power,but there are few studies on the thermal effect of Er:Yb:glass.When the laser interacts with the gain medium,a portion of the pump light absorbed by the crystal will be converted to heat and stored in the crystal,resulting in a rise in its temperature,which becomes one of the factors limiting the output energy.The influence of thermal effect on the laser has two main aspects.On the one hand,as the laser crystal temperature increases,the fluorescence spectral line will broaden and the quantum efficiency will decrease,which will eventually lead to the decrease of conversion efficiency.On the other hand,the thermal stress and thermal lens effect generated by the temperature gradient will seriously affect the output stability and beam quality of the laser.Therefore,it is necessary to investigate the heat treatment capability of Er:Yb:glass as gain medium in order to develop a scheme for further optimization of the output performance.Methods The heat accumulation process inside Er:Yb:glass as the gain medium is calculated in detail by finite element analysis method.Assuming that the surface temperature of the crystal is constant with the ambient temperature,the heat generated inside the medium is mainly dissipated by heat conduction,and the outer surface is affected by natural heat convection of air.When the LD is end-pumped with Er:Yb:glass,the pump source acts as an internal heat source and operates with a temperature gradient,which triggers the heat conduction process(Fig.2).In order to compare the heat dissipation performance of the gain medium under different conditions,the simulation is carried out after reaching steady state.The crystal model was divided according to the ultra-fine grid,and the effects of non-bonded and bonded crystals as well as different pump wavelengths,powers and beam waist radius o

关 键 词：LD端面泵浦 Er:Yb:glass/Co:MALO 调Q激光器 热效应 热应力 

分 类 号：TN24[电子电信—物理电子学]