The dephasing of coherent phonons in GaAs [100]

The dephasing of coherent LO phonons due to excess photoexcited carriers in the near surface region of the GaAs [100] crystal is investigated with a time-resolved second-harmonic generation technique. The dephasing process was accelerated by the pre-injected carriers through carrier-phonon scattering and incoherent phonon-phonon scattering.