Study of coherent folded acoustic phonons in GaAs/AlAs superlattices by two-color pump-probe technique

Abstract

We have observed coherent folded longitudinal acoustic phonons in periodic superlattices by one- and two-color pump-probe measurements. The time-resolved spectrum with violet pump and near-IR probe beams indicates that the coherent folded acoustic phonons generated near the surface propagate to a substrate and are observed only when the acoustic phonons propagate in the superlattice layer.