对全固态SESAM锁模激光器的锁模特性进行了理论研究。基于抑制调Q锁模理论模型和结合全固态LD抽运的Yb:YAG激光器等,数值模拟分析了在不同调制深度、非饱和损耗、饱和通量和输出镜透射比等参数下的SESAM的反射率,以及抑制调Q锁模所需要的临界抽运功率。以同样的脉冲通量入射到SESAM上,SESAM的调制深度、非饱和损耗和饱和通量与它的反射率都呈一个反比关系。调制深度、饱和通量、输出镜透射比、激光光腰和腔长的减小都会降低临界抽运功率,使其更容易抑制调Q锁模。在晶体长度为1.9 mm时,可获得最小临界抽运功率。

Theoretical research on the mode locking characteristics of mode-locked all-solid-state laser with semiconductor saturable absorber mirror has been carried out. According to theoretical model of suppressing Q-switched mode locking and combining with LD-pumped all-solid-state Yb:YAG laser,the reflectivity of SESAM and the critical pump power of suppressing Q-switched mode locking have been studied by numerical simulated calculations under the conditions of different modulation depths,non-saturable losses,saturation fluences,transmittance of the output mirror and other parameters. When the incident pulse fluences on the SESAM are the same,modulation depth,non-saturable loss and saturation fluence have inverse relations with SESAM reflectivity. With the decrease of modulation depth,saturation fluence,transmittance of the output mirror,beam waist and cavity length,the critical pump power also decreases,and suppressing Q-switched mode locking becomes easier. When the crystal length is 1.9 mm,the minimum critical pump power can be obtained.