Abstract
We report on the observation of nearly maximally entangled photon pairs from semiconductor quantum dots, without resorting to postselection techniques. We use GaAs quantum dots integrated on a patterned piezoelectric actuator capable of suppressing the exciton fine structure splitting. By using a resonant two-photon excitation, we coherently drive the biexciton state and demonstrate experimentally that our device generates polarization-entangled photons with a fidelity of 0.978(5) and a concurrence of 0.97(1) taking into account the nonidealities stemming from the experimental setup. By combining fine-structure-dependent fidelity measurements and a theoretical model, we identify an exciton spin-scattering process as a possible residual decoherence mechanism. We suggest that this imperfection may be overcome using a modest Purcell enhancement so as to achieve fidelities , thus making quantum dots evenly matched with the best probabilistic entangled photon sources.
- Received 1 February 2018
DOI:https://doi.org/10.1103/PhysRevLett.121.033902
© 2018 American Physical Society
Physics Subject Headings (PhySH)
Synopsis
Quantum Dots Serve Entangled Photons on Demand
Published 18 July 2018
Quantum dots that emit entangled photon pairs on demand could be used in quantum communication networks.
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