Generation and characterization of polarization-entangled states using quantum dot single-photon sources

TL;DR

This paper demonstrates a compact quantum dot-based source that reliably generates high-quality polarization-entangled photon pairs, advancing practical quantum information processing applications.

Contribution

It introduces a simple, stable platform for entangled photon generation using quantum dots with two excitation schemes and comprehensive state characterization.

Findings

High entanglement fidelity achieved

Stable long-term operation demonstrated

Effective modeling of experimental parameters

Abstract

Single-photon sources based on semiconductor quantum dots find several applications in quantum information processing due to their high single-photon indistinguishability, on-demand generation, and low multiphoton emission. In this context, the generation of entangled photons represents a challenging task with a possible solution relying on the interference in probabilistic gates of identical photons emitted at different pulses from the same source. In this work, we implement this approach via a simple and compact design that generates entangled photon pairs in the polarization degree of freedom. We operate the proposed platform with single photons produced through two different pumping schemes, the resonant excited one and the longitudinal-acoustic phonon-assisted configuration. We then characterize the produced entangled two-photon states by developing a complete model taking into account relevant experimental parameters, such as the second-order correlation function and the Hong-Ou-Mandel visibility. Our source shows long-term stability and high quality of the generated entangled states, thus constituting a reliable building block for optical quantum technologies.