热透镜的球差效应对大基模体积激光谐振腔模式的影响

固体激光器在强抽运的条件下，激光晶体热透镜的球差效应是不容忽视的，尤其是在大基模体积的动态稳定腔中，会影响谐振腔的振荡模式，进而影响腔内损耗和输出功率.通过Fox-Li的衍射迭代算法，分析了谐振腔的自再现模，表明在热透镜球差效应作用下，基模的光强分布出现了旁瓣，并由此带来了光束质量的下降，最后通过实验结果验证了理论分析，指出光束填充因子是激光器设计的一个重要因素，其最佳值需要根据球差效应的强弱，通过实验的方法来确定. 关键词： 热透镜 球差效应 谐振腔模式

Influence of spherical aberration of the thermal lens on the mode profile of a large-volume TEM00-mode resonator

The spherical aberration of the thermal lens of the active media is obvious when the solid state lasers are strongly pumped. It can change the mode profile, the single-pass loss, the output power and so on, especially in a large-volume TEM₀₀-mode resonator. The self-consistent mode is calculated using Fox-Li diffraction iterative algorithm. There are side lobes with the fundamental mode when the spherical aberration is introduced, hence the beam quality is degraded. The calculation results agree well with the experimental results. The beam filling factor plays an important role in the design of a laser system. The optimized value of the beam filling factor should be determined experimentally according to the spherical aberration.