简要介绍了在飞秒激光器中提供自启动机制的半导体可饱和吸收镜(SESAM)的主要功能特点以及相关膜层结构的发展过程； 着重阐述了半导体可饱和吸收镜膜层结构中电场分布以及反射率和反射带宽的影响，同时对三种不同结构的半导体可饱和吸收镜反射率作了分析比较。

This paper introduced the main characterstics and relative development process of the thin films constructions of semiconductor saturable absorber mirror, which supported the self starting mechanism in the femtosecond lasers. The great emphases were focused on the contribution of the electrical fields of the thin films constructions and the affection due to the reflectivity and the bandwidth. Also the comparison of reflectivity for the three different constructions in semiconductor saturable absorber mirror was made.