Polarisation control and emission enhancement of a quantum dot in ultra-high finesse microcavity pillars

The polarised cavity modes of a semiconductor microcavity pillar with elliptical cross-section can be used to enhance the photoluminescence (PL) emission of a quantum dot. We study dots embedded within very high Q value elliptical microcavity pillars, where the two orthogonally polarised modes are very well resolved. We show that a dot that emits unpolarised PL when off-resonance with the cavity mode becomes around 95% linearly polarised when on-resonance. Such a device could form the basis of an efficient source of polarised single photons for use in quantum cryptography experiments.