Polarization control of quantum dot single-photon sources via a dipole-dependent Purcell effect

We study single photon emission from excitons confined in single InAs quantum dots in elliptical pillar microcavities, demonstrating a polarization dependence of the Purcell effect. The enhancement of the radiative decay rate and emission intensity differs for the two components of the exciton doublet, suggesting each exciton state corresponds to a well-defined dipole direction in the sample plane. This allows the linear polarization of the single photon source to be selected between orthogonal directions by tuning the exciton emission energy between different polarization modes of the cavity.