激光二极管叠阵单侧抽运Nd:YAG陶瓷聚光腔的聚光特性

Light Collecting Characteristics of Nd:YAG Ceramic Condenser Chamber Unilaterally Pumped by Laser Stacked Array

针对固体激光增益模块紧凑化、简单化的设计需求,建立了激光二极管(LD)叠阵单侧抽运Nd:YAG晶体棒的模型,并利用TracePro软件对陶瓷聚光腔内Nd:YAG晶体棒抽运光的吸收情况进行了数值模拟。分析了聚光腔形状、晶体棒半径和Nd3+掺杂浓度及其他影响因素对聚光效率和增益分布均匀性的影响。研究表明,聚光效率随聚光腔横截面积近似呈线性变化,Nd^(3+)掺杂原子数分数为0.5%、半径为2mm的Nd:YAG晶体棒可以实现光斑半径约为1.0mm的近基模振荡输出;晶体棒均匀抽运区域半径与U型聚光腔半径的比值约为0.5时,抽运光吸收较为均匀。LD叠阵单侧抽运Nd:YAG晶体的抽运结构可以获得65%的聚光效率,增益分布均匀性优于0.65。

For the requirements of compact and simplified solid laser gain module structure design, a model of Nd： YAG crystal rod unilaterlly pumped by laser diode （LD） stacked array is built. The absorbed light distribution within the Nd： YAG crystal rod in ceramic condenser chamber is simulated with the TracePro software. The influences of condenser chamber＇s shape, crystal rod＇s radius and doping concentration of Nd^3＋ on the light collecting efficiency and the gain distribution uniformity are studied. The research shows that the light collecting efficiency changes approximately linearly with the cross-sectional area of the condenser chamber. ANd： YAG crystal rod with radius of 2 mm and Nd^3＋ doping concentration of 0.5 % （atom fraction） can obtain near fundamental mode oscillation output with 1.0 mm spot radius. The distribution of absorbed pumping light is more uniform when the ratio of the uniform pumping area radius of crystal rod to the U-shape condenser chamber radius is about 0.5. With the discussed structure, the light collecting efficiency reaches 65%, while the gain distribution uniformity is better than 0.65 in the LD stacked array unilaterally pumped Nd： YAG crystal structure.