Nd:YAG棒中的热光效应计算

激光通过工作物质时所产生的热透镜以及应力双折射两种效应是高功率二极管泵浦激光器(DPL)的设计和优化过程中必需考虑的因素.讨论了采用有限差分光束传播法计算热透镜效应及结合材料的弹光系数矩阵计算应力双折射效应的一般方法,并具体针对长6 cm、均匀泵浦的NdYAG棒,计算了这两种效应对光束的影响.结果表明,由于热透镜的聚焦效应,棒中心的光场振幅在通过棒后增大了6%,棒中心与边缘产生了20个波长的相位差;同时,应力引起的双折射造成了约30%的功率损失.

Calculation of thermo-optical effects in Nd:YAG rod

Thermal lens and stress induced birefringence are two key effects that must be considered in the design and optimization of high-power DPL. This paper discusses the general way of calculating the thermal lens by finite-difference beam propagation method and that of calculating the stress induced birefringence using the elasto-optical coefficients of the material. The effects of the thermal lens and the stress induced birefringence on beams were calculated for a 6 cm Nd:YAG rod. The results show that the wavefront amplitude in the center of the rod increases about 6% after one pass, and the wavefront phase difference between the center and the edge of the rod reaches nearly 20 wavelengths; meanwhile, about 30% power losses due to birefringence.