Coherent acoustic phonon oscillations in superlattices

Abstract

Resonant impulsive stimulated Raman scattering is shown to be the driving force for coherent acoustic phonons in semiconductor superlattices. Three modes are observed for the first two backfolded phonon branches, which are assigned to q=0 and q=2klaser excitation via forward and backward scattering, respectively. Modes of different backfolded branches are controlled coherently.