全固态石墨烯锁模激光器的脉冲特性分析

Pulse Characteristics Analysis of All-Solid-State Mode-Locked Laser with Graphene

为研究腔参数和石墨烯的可饱和吸收特性对脉冲特性的影响,数值求解了描述激光器动力学的Haus主方程。采用饱和吸收体的快饱和模型,分析了谐振腔腔长、石墨烯层数、输出镜透射率和激光晶体上光斑半径的变化对脉冲特性的影响,并与半导体可饱和吸收镜(SESAM)做了比较。结果表明,石墨烯和SESAM各具优势,例如在腔长短且可饱和吸收体上光斑半径小时选择石墨烯,在腔长长且光斑半径大时选择SESAM,分别能获得峰值功率更高的脉冲激光。故应根据具体的实验情况选择适当的可饱和吸收体和腔参数。

The Haus master equation which describes the laser dynamics is solved numerically so as to study the effects of cavity parameters and characteristics of graphene saturable absorber on the pulses characteristics. Adopting the fast saturable absorber model, the relations between pulse characteristics with cavity length, graphene layers, transmittances of output mirror and beam radius on the laser medium are analyzed. In addition, the results are compared with that of semiconductor saturable absorption miror （SESAM）. The conclusions show that the graphene and SESAM have different advantages. For example, for higher pulse energy, graphene is favorable for shorter cavity length and smaller radius on saturable absorber, while the SESAM is better for the opposite situation. The saturable absorbers and cavity parameters should be chosen properly according to concrete situations.