Observation of strongly entangled photon pairs from a nanowire quantum dot

TL;DR

This paper reports the first demonstration of strongly entangled photon pairs from a nanowire quantum dot, achieving high fidelity and concurrence, with potential applications in quantum information processing.

Contribution

It presents the experimental realization of a bright, coherent, and position-controlled nanowire quantum dot as a source of entangled photons, previously only predicted theoretically.

Findings

Fidelity of 0.859 +/- 0.006 for entangled photon pairs.

Concurrence of 0.80 +/- 0.02 indicating strong entanglement.

Nanowire shape modifies the two-photon quantum state.

Abstract

A bright photon source that combines high-fidelity entanglement, on-demand generation, high extraction efficiency, directional and coherent emission, as well as position control at the nanoscale is required for implementing ambitious schemes in quantum information processing, such as that of a quantum repeater. Still, all of these properties have not yet been achieved in a single device. Semiconductor quantum dots embedded in nanowire waveguides potentially satisfy all of these requirements; however, although theoretically predicted, entanglement has not yet been demonstrated for a nanowire quantum dot. Here, we demonstrate a bright and coherent source of strongly entangled photon pairs from a position controlled nanowire quantum dot with a fidelity as high as 0.859 +/- 0.006 and concurrence of 0.80 +/- 0.02. The two-photon quantum state is modified via the nanowire shape. Our new nanoscale entangled photon source can be integrated at desired positions in a quantum photonic circuit, single electron devices and light emitting diodes.