Hudson, A. J. and Stevenson, R. M. and Bennett, A. J. and Young, R. J. and Nicoll, C. A. and Atkinson, P. and Cooper, K. and Ritchie, D. A. and Shields, A. J. (2007) Coherence of an entangled exciton-photon state. Physical review letters, 99 (26): 266802. -. ISSN 0031-9007
Full text not available from this repository.Abstract
We study the effect of the exciton fine-structure splitting on the polarization entanglement of photon pairs produced by the biexciton cascade in a quantum dot. Entanglement persists despite separations between the intermediate energy levels of up to 4 mu eV. Measurements show that entanglement of the photon pair is robust to the dephasing of the intermediate exciton state responsible for the first-order coherence time of either single photon. We present a theoretical framework incorporating the effects of spin scattering, background light, and dephasing. We distinguish between the first-order coherence time, and a parameter which we measure for the first time and define as the cross-coherence time.