Quantum Correlations and Intraband Coherences in Semiconductor Cavity QED

A fully quantized theory of optical interactions with semiconductors reveals quantum correlations between the field and carrier density. These quantum correlations lead to intraband coherences which live much longer than the interband dephasing time; the correlations are observed as oscillations in the time-resolved reflectivity in a pump-probe experiment on a normal-mode microcavity. Coherent control of the microcavity normal modes using phase-locked pump pulses enables considerable enhancement of the intraband oscillations due to quantum interference; the detailed phase dependence is well reproduced by the theory.