Picsecond grating dynamics in GaAs and CdTe at 1.064 um

摘要

Abstract: Laser-induced transient gratings generated by picosecond pulses at 1.064 $mu@m in GaAs and CdTe samples were used to diffract a picosecond probe pulse in the degenerate-four-wave- mixing geometry. Pulse and probe experiments performed using the same experimental set-up allowed us to measure the free-carrier lifetime. The ambipolar diffusion coefficient D was then determined by using only one laser-material geometrical configuration. In semi-insulating GaAs:Cr and CdTe:W, gratings persisted for more than one nanosecond and could be partially erased using a homogeneous picosecond pulse, the energy of which was one quarter of the writing energy. We present a model which explains these results. !11