Tailoring solid-state single-photon sources with stimulated emissions

TL;DR

This paper demonstrates a method to enhance solid-state single-photon sources using stimulated emission in a three-level quantum dot system, significantly improving photon purity and indistinguishability for quantum technologies.

Contribution

It introduces a novel approach to tailor emission dynamics in three-level quantum dot systems via stimulated emission, enhancing single-photon source performance.

Findings

Achieved a photon purity of 0.998

Realized an indistinguishability of 0.926

Demonstrated improved source brightness

Abstract

The coherent interaction of electromagnetic fields with solid-state two-level systems can yield deterministic quantum light sources for photonic quantum technologies. To date, the performance of semiconductor single-photon sources based on three-level systems is limited mainly due to a lack of high photon indistinguishability. Here, we tailor the cavity-enhanced spontaneous emission from a ladder-type three-level system in a single epitaxial quantum dot (QD) through stimulated emission. After populating the biexciton (XX) of the QD through two-photon resonant excitation (TPE), we use another laser pulse to selectively depopulate the XX state into an exciton (X) state with a predefined polarization. The stimulated XX-X emission modifies the X decay dynamics and yields improved polarized single-photon source characteristics such as a source brightness of 0.030(2), a single-photon purity of 0.998(1), and an indistinguishability of 0.926(4). Our method can be readily applied to existing QD single-photon sources and expands the capabilities of three-level systems for advanced quantum photonic functionalities.