Abstract

A proper description of subpicosecond four-wave-mixing (FWM) experiments for excitonic transitions in semiconductor heterostructures must consider the fact that the spectrally broad laser pulses excite not only the 1s bound exciton state but also energetically higher bound exciton states and the lower-lying part of the unbound continuum states. In this paper, we report results of transient and time-resolved FWM-experiments in which such ’excitonic wave packets’ play a crucial role. In addition, a theoretical treatment of the problem based on the solution of the semiconductor Bloch is presented. We show that the time-dependent nonlinear response is determined by an interplay between inhomogeneous broadening and Coulomb interaction.

© 1994 Optical Society of America