Improved fidelity of triggered entangled photons from single quantum dots

Abstract

We demonstrate the on-demand emission of polarisation-entangled photon pairs\nfrom the biexciton cascade of a single InAs quantum dot embedded in a GaAs/AlAs\nplanar microcavity. Improvements in the sample design blue shifts the wetting\nlayer to reduce the contribution of background light in the measurements.\nResults presented show that >70% of the detected photon pairs are entangled.\nThe high fidelity of the (|HxxHx>+|VxxVx>)/2^0.5 state that we determine is\nsufficient to satisfy numerous tests for entanglement. The improved quality of\nentanglement represents a significant step towards the realisation of a\npractical quantum dot source compatible with applications in quantum\ninformation.\n