Role of incoherent pumping in a strongly coupled system of exchange-split excitons and pillar-microcavities

We present an experimental study of the influence of incoherent pumping upon the strong coupling between quantum dot excitons and a micropillar-cavity. For two exchange-split excitons, the inherent difference in the detuning with respect to the cavity modes leads to an unequal reduction of Rabi splitting for two orthogonal polarizations as excitation power is increased, which could destroy the indistinguishable decay paths built by the coupled states. This work prompts a careful implementation of optical pumping for the pursuit of polarization-entangled photon pairs in the strong coupling regime.