端面抽运方形复合YAG温度场及热透镜研究  

Investigation on Temperature and Thermal Lens Effects of Laser Diode End Pumped Quadrate Composite YAG Crystal

作　　者：李锋[1] 范婷[1] 白晋涛[1] 侯洵[1] 

机构地区：[1]西北大学光子学与光子技术研究所

出　　处：《光子学报》2008年第3期425-429,共5页Acta Photonica Sinica

基　　金：陕西省教育厅专项基金(05JK185,04JK125)资助

摘　　要：采用数值方法研究了方形截面复合Nd∶YAG激光晶体棒在端面抽运情况下的温度分布及热透镜效应,得到复合激光晶体内温度场的数值解和径向温度梯度引起的轴向传播光相位延迟分布ΔΦT(r),并与同条件下普通晶体的结果进行了比较.结果表明,吸收系数越大,两种晶体中最高温度相差也越大.采用复合晶体可以大幅度降低激光晶体内的温升,同时减小端面形变造成的透镜效应.复合晶体的ΔΦT(r)与普通晶体相似,且不满足对半径r的二次方关系.在r<wp时,这一相位延迟分布可近似等效于一球面透镜,其等效焦距fGRIN值与普通晶体的接近;但在r>wp时,ΔΦT(r)相对于参考球面透镜的相位畸变Δφ随r的增大而急剧增大.Temperature field and thermal lens effects of laser diode end pumped quadrate composite Nd ： YAG rod are investigated through numerical analysis methods. Numerical solution of temperature field for end pumped configuration is obtained, as well as phase-retardation distribution △ФT （r） for the axial light caused by radial temperature gradient, and the results are compared with conventional crystal under the same pump condition. The results show that in both composite and conventional crystal, the differences of their highest temperature increase as the absorption coefficient increasing. Composite crystal leads a lower temperature rise in laser crystal, and also reduces the portion lens effect from the lessened distortion of pump end. △ФT（r） in composite crystal is similar to that of conventional one, and it does not accord with radius quadratic relationship. There is an aberration △φ between the phase retardation of the thermal lens and referenced spherical lens. △ФT（r） corresponds with that of a spherical lens approximately at r〈Wp, and the equivalent loci foci approaches to the same value of conventional rod, whereas △φ increased quickly with the increase of laser beam radius at r〉Wp.

关 键 词：激光物理 温度场 数值分析 复合YAG激光晶体 热透镜效应 

分 类 号：TN248.1[电子电信—物理电子学]