基于梯度掺杂晶体的激光器模式匹配研究  

Research on Laser Mode Matching Based on Gradiently-Doped Crystal

作　　者：满朝阳 崔璨[1,2] 王雨雷 刘福寒 李银栋 白振旭 吕志伟 Man Zhaoyang;Cui Can;Wang Yulei;Liu Fuhan;Li Yindong;Bai Zhenxu;LüZhiwei(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：《中国激光》2024年第5期1-11,共11页Chinese Journal of Lasers

基　　金：国家自然科学基金(62075056,61927815);天津市自然科学基金(20JCZDJC00430);河北省高等学校科学技术研究项目青年基金项目(QN2023173)。

摘　　要：针对梯度掺杂晶体和均匀掺杂晶体,采用数值模拟的方式分析了泵浦光束腰半径、光束质量因子(M^(2))与束腰位置对模式匹配效率的影响,并通过实验验证了不同束腰位置对激光器输出功率的影响。由计算结果得到,在不同的泵浦光参数下,与均匀掺杂晶体相比,梯度掺杂晶体均具有更稳定的模式匹配;当泵浦光M^(2)为10和50,束腰半径为0.5 mm时,对于任意位置的束腰,梯度掺杂晶体的模式匹配效率都高于均匀掺杂晶体。在实验上对比分析了泵浦光不同束腰位置的输出功率,结果表明,梯度掺杂晶体的模式匹配效率受泵浦光束腰位置的影响较小。当晶体位于谐振腔中心时,在高于70 W的泵浦条件下,梯度掺杂晶体的输出功率高于均匀掺杂晶体,最高输出功率为44.8 W,与均匀掺杂晶体相比,提高了4.67%;当晶体紧贴输入镜时,梯度掺杂晶体的最高输出功率为34.0 W,与均匀掺杂晶体相比,提高了11.84%。因此,梯度掺杂晶体更适用于高功率泵浦。Objective End-pumped lasers offer the advantages of high efficiency,good beam quality,and compact structure.However,the exponential decay of pump absorption along the longitudinal direction in commonly used conventional uniformly-doped crystals,produces a large temperature gradient,which leads to a series of thermal problems such as severe thermal lensing effects and end-face deformation,inevitably leading to the deterioration of laser performance.In addition,the thermal stress restricts the pump power limit,beyond which thermal stress leads to crystal damage.Currently,many researchers use gradiently-doped crystals to improve the thermal effect and reduce the temperature gradient.Gradiently-doped crystals are simple in structure,and yet improve the pumping limit with excellent performance in high-power pumping;however,the different concentration distributions of gradiently-doped crystals cause the mode-matching to differ from that of traditional uniformly-doped crystals.Therefore,maximizing the advantages of the gradiently-doped crystal is still a difficult problem.At present,research on the mode-matching of gradiently-doped crystals is lacking.Consequently,studying the mode-matching problem in end-pumped gradiently-doped crystal lasers is of great significance.Methods In this study,the effects of pump beam waist radius,beam quality factor(M^(2))value,and waist position on the modematching efficiencies of gradiently-doped and uniformly-doped crystal lasers are theoretically calculated.Subsequently,the effect of pump beam waist position on mode-matching of gradiently-doped crystal lasers is experimentally investigated by changing the pump beam waist position when the radius is 0.4 mm and 0.5 mm,respectively.Finally,the crystals are placed at the center of the resonant cavity and at a position close to the input mirror,with pump beam waist radius of 0.5 mm and beam waist position close to the pump input face of the crystals,to study the performance of gradiently-doped and uniformly-doped crystals under high-power p

关 键 词：激光器 梯度掺杂晶体 模式匹配 激光器理论 端面泵浦 高功率激光 

分 类 号：TN248.1[电子电信—物理电子学]