Physica status solidi. C, Conferences and critical reviews/Physica status solidi. C, Current topics in solid state physics
Polarization dependence of quantum beats in quantum wells: Raman coherence and two‐exciton correlations
Scot A. Hawkins, Eric J. Gansen, Martin J. Stevens, I. Rumyantsev, Ryu Takayama, N. H. Kwong, Rolf H. Binder, G. Khitrova, H. M. Gibbs, Duncan G. Steel, Arthur L. Smirl
Abstract
Time-integrated differential detection techniques are used to study quantum beats involving the light-hole and heavy-hole excitons in an optically thin InGaAs multiple quantum well. The contributions of the exciton-exciton correlations are separated from those of the intervalence-band Raman coherence and the interband (population) coherence by monitoring the signal in the probe direction and by taking advantage of the polarization selection rules for the excitonic transitions. Quantum beats are observed for pump and probe pulses with the same circular polarization, providing evidence for two-exciton correlations. A theoretical analysis based on the dynamics-controlled truncation formalism suggests that the beats for the same linear polarization arise from Raman, population, and two-exciton contributions.