Study of coherent folded acoustic phonons in semiconductor superlattices by pump-probe technique

Abstract

We report on the time-resolved study of coherent folded longitudinal acoustic phonons propagating in GaAs/AlAs superlattices using a two-color pump-probe technique with violet pump and near-IR probe pulses. From comparing the frequencies of the observed coherent phonons with the dispersion relations, we find that the wavevectors of the propagating coherent folded acoustic phonons depend on the wavevector of the probe light: q=2 k probe.