为了提高V型谐振腔的热稳定性,采用了图解分析法,将V型折叠腔等效为腔内含有一个透镜的共轴球面腔。同时考虑到晶体热透镜效应,结合多元件光学谐振腔的等价腔分析法,将等效后腔内含透镜组的多元件球面腔近似等价为腔内不含透镜的共轴球面空腔。对V型腔等价后的共轴球面空腔的稳定性进行了理论计算和仿真分析。结果表明,当总腔长为75mm、折叠角为0.15π左右时,谐振腔具有最宽的热稳定范围; 此时若增益介质与折叠镜的间距为28mm,则谐振腔能适应的最小热透镜焦距可达12mm。这一结果体现了谐振腔关键参量对热稳定性的重要影响,对激光腔型稳定性的优化设计具有一定的指导意义。

In order to improve the thermal stability of V-type resonant cavity, based on graphic analysis, a simple V-type folded cavity was transformed into a coaxial spherical cavity with a thin lens. At the same time, considering the thermal effect of lens and combining with equivalent cavity analysis method of multi element optical resonator, the V-type folded cavity with lens group was transformed into a coaxial spherical cavity with no lens in the cavity. And the thermal stability of coaxial spherical cavity with no lens was calculated and analyzed. The results show that, the cavity has the widest range of thermal stability when the total cavity is 75mm and the fold angle is 0.15π. When the interval between the gain medium and folding mirror is 28mm, the focal length of the minimum thermal lens being suitable for the cavity can reach 12mm. The study shows that the key parameters of the cavity are important to thermal stability, and it has guiding significance for the optimization design of laser cavity stability.