Enhanced correlated photon pair emission from a pillar microcavity

We demonstrate the efficient generation of triggered photon pairs by placing a single quantum dot (QD) into a micropillar cavity. Photon cross-correlation measurements between biexciton and exciton decay reveal a bunching effect under pulsed excitation due to the cascaded nature of the emission. No polarization correlation between the exciton and biexciton emission is observed. Furthermore, the emission mode structure of the pillar microcavities is investigated within a theory-experiment comparison where calculations are based on an extended transfer matrix method. Efficient mode confinement perpendicular to the emission direction leads to a series of transverse modes combined with enhanced QD emission. For the photoluminescence (PL) intensity of QDs in pillar microcavities (0.6 μm diameter), an enhancement factor of 40 was found in comparison to the PL intensity of QDs in bulk semiconductors, reflecting the enhanced photon collection effect out of the cavity structure.