Electronic Raman coherence in GaAs: state-specific scattering processes

Summary form only given. Quantum beats probe energy gaps and coherences, including the nonradiative Raman correlation between the light- and heavy-hole valence bands. A recent analysis of quantum beats in four-wave mixing (FWM) in a multiple-quantum well (MQW) illustrates the potential of this technique. We have demonstrated the existence of a Raman coherence, independent of polarization beats. The fast decay and polarisation dependence reveal strongly state specific scattering and spin independent interactions.