Tunable quantum dots in monolithic Fabry-Perot microcavities for high-performance single-photon sources

TL;DR

This paper presents a tunable Fabry-Perot microcavity integrated with quantum dots, achieving high Purcell factor, efficiency, purity, and indistinguishability for scalable on-chip single-photon sources in quantum technologies.

Contribution

The work demonstrates a miniaturized, strain-tunable microcavity with integrated quantum dots, enabling scalable, high-performance single-photon sources with precise spectral control.

Findings

Achieved a Purcell factor of approximately 9.

Single photons with efficiency 0.58, purity 0.956, and indistinguishability 0.922.

Enabled spectral tuning via strain with piezoelectric actuation.

Abstract

Cavity-enhanced single quantum dots (QDs) are the main approach towards ultra-high-performance solid-state quantum light sources for scalable photonic quantum technologies. Nevertheless, harnessing the Purcell effect requires precise spectral and spatial alignment of the QDs' emission with the cavity mode, which is challenging for most cavities. Here we have successfully integrated miniaturized Fabry-Perot microcavities with a piezoelectric actuator, and demonstrated a bright single photon source derived from a deterministically coupled QD within this microcavity. Leveraging the cavity-membrane structures, we have achieved large spectral-tunability via strain tuning. On resonance, we have obtained a high Purcell factor of approximately 9. The source delivers single photons with simultaneous high extraction efficiency of 0.58, high purity of 0.956(2) and high indistinguishability of 0.922(4). Together with a small footprint, our scheme facilitates the scalable integration of indistinguishable quantum light sources on-chip, and therefore removes a major barrier to the solid-state quantum information platforms based on QDs.