Abstract

Resonant excitation of excitons by short optical laser pulses creates a macroscopic polarization which decays in the simplest case with a constant rate described by the dephasing time T₂. In semiconductors and semiconductor quantum well structures this dephasing time is of the order of 1ps. Thus, subpicosecond time resolution is required to study coherent exciton effects in quantum wells. We have applied femtosecond Four-Wave-Mixing (FWM) spectroscopy in our studies. As more than one exciton state is excited simultaneously, the coherent dynamics and interaction of these exciton states can be studied.

© 1993 Optical Society of America