Bright Polarized Single-Photon Source Based on a Linear Dipole

TL;DR

This paper introduces a highly polarized, efficient, and pure single-photon source using a linear dipole in a quantum dot, advancing quantum communication technologies.

Contribution

It demonstrates a deterministic, polarized single-photon source leveraging phonon-assisted excitation of a quantum dot's linear dipole, achieving high polarization and purity.

Findings

Degree of linear polarization up to 0.994

Single-photon purity of 0.954

Polarized brightness of 0.50

Abstract

Semiconductor quantum dots in cavities are promising single-photon sources. Here, we present a path to deterministic operation, by harnessing the intrinsic linear dipole in a neutral quantum dot via phonon-assisted excitation. This enables emission of fully polarized single photons, with a measured degree of linear polarization up to 0.994 $\pm$ 0.007, and high population inversion -- 85\% as high as resonant excitation. We demonstrate a single-photon source with a polarized first lens brightness of 0.50 $\pm $ 0.01, a single-photon purity of 0.954 $\pm$ 0.001 and single-photon indistinguishability of 0.909 $\pm$ 0.004.