Differential measurements of interband and intersubband coherence and exciton-exciton correlations in quantum wells

A novel temporally-gated technique and standard differential detection techniques are used to study quantum beats involving the light and heavy hole excitons in GaAs quantum wells. The contributions of intravalence band coherence are separated from those of conduction-to-valence band coherence and the contributions of dynamic exciton-exciton correlations are identified by taking advantage of the polarization selection rules for the excitonic transitions.