Improved fidelity of triggered entangled photons from single quantum dots

Young, Robert J. and Stevenson, R. Mark and Atkinson, Paola and Cooper, Ken and Ritchie, David A. and Shields, Andrew J. (2006) Improved fidelity of triggered entangled photons from single quantum dots. New Journal of Physics, 8 (2): 29. ISSN 1367-2630

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Abstract

We demonstrate the triggered emission of polarization-entangled photon pairs from the biexciton cascade of a single InAs quantum dot embedded in a GaAs/AlAs planar microcavity. Improvements in the sample design blue shifts the wetting layer to reduce the contribution of background light in the measurements. Results presented show that > 70% of the detected photon pairs are entangled. The high fidelity of the (|HXXHX) + |VXXVX])/root 2 state that we determine is sufficient to satisfy numerous tests for entanglement. The improved quality of entanglement represents a significant step towards the realization of a practical quantum dot source compatible with applications in quantum information.