飞秒激光诱发直接带隙半导体瞬态漂白效应建模

Model of Transient Bleaching Effect of the Direct Bandgap Semiconductor Induced by Femtosecond Laser

在建立瞬态光谱吸收系数模型的基础上,结合超快载流子动力学机制,建立了可以描述飞秒激光诱发直接带隙半导体瞬态漂白机制的理论模型,对飞秒激光诱发直接带隙半导体的瞬态漂白特性进行了数值仿真研究。结果表明,飞秒激光不仅可以诱发对应波长的瞬态漂白,还能导致激发波长到半导体长波限的宽光谱范围的瞬态漂白,且波长越长漂白现象越明显,甚至会引发能带底部出现负吸收现象。

On the basis of the development of the model of transient state spectral absorption coefficient and ultrafast carrier dynamics,a theoretical model is established,which can describe the transient bleaching mechanism induced by femtosecond laser,so as to investigate the characteristics of the transient bleaching of direct bandgap semiconductor.The results indicate that femtosecond laser can not only induce the corresponding spectral bleaching but bleach the spectrum ranging from the exciting wavelength to the semiconductor′s long wavelength cutoff as well,and the effect becomes more obviously with the increase of laser wavelength and even results in negative absorption phenomena at the bottom of band.