Partially and completely non-degenerate four-wave mixing experiments in GaAs quantum wells: a new component with a below-the-bandgap pump beam

Summary form only given. Recently, non-degenerate inter-level interactions caused by Coulomb correlations have been studied by using partially non-degenerate four-wave mixing. The most important signature of this interaction was the existence of strong coherent emission at the exciton resonance even when the first pulse (/spl omega//sub 1/) excites continuum that is non overlapping to the exciton resonance. We have performed femtosecond non-degenerate four-wave mixing by using a synchronized independently tunable Ti:sapphire laser pair or by selecting two energies from a broad femtosecond laser spectrum.