Femtosecond studies on the optical-induced refractive index change in GaAs film

摘要

The dynamics of the optical induced refractive index change and the absorption change in GaAs film is studied using femtosecond transmission and reflection spectroscopy. A rapid variation of the optical induced refractive index and an increased optical induced absorption are observed. These phenomena are interpreted with the band filling and the bandgap shrinking effect of the excited carriers.