A quantum-light source that delivers photons with a high brightness and a high degree of entanglement is fundamental for the development of efficient entanglement-based quantum-key distribution systems. Among all possible candidates, epitaxial quantum dots are currently emerging as one of the brightest sources of highly entangled photons. However, the optimization of both brightness and entanglement currently requires different technologies that are difficult to combine in a scalable manner. In this work, we overcome this challenge by developing a novel device consisting of a quantum dot embedded in a circular Bragg resonator, in turn, integrated onto a micromachined piezoelectric actuator. The resonator engineers the light-matter interaction to empower extraction efficiencies up to 0.69(4). Simultaneously, the actuator manipulates strain fields that tune the quantum dot for the generation of entangled photons with corrected fidelities to a maximally entangled state up to 0.96(1). This hybrid technology has the potential to overcome the limitations of the key rates that plague QD-based entangled sources for entanglement-based quantum key distribution and entanglement-based quantum networks.
@article{arxiv.2212.12506,
title = {A source of entangled photons based on a cavity-enhanced and strain-tuned GaAs quantum dot},
author = {Michele B. Rota and Tobias M. Krieger and Quirin Buchinger and Mattia Beccaceci and Julia Neuwirth and Hêlio Huet and Nikola Horová and Gabriele Lovicu and Giuseppe Ronco and Saimon F. Covre da Silva and Giorgio Pettinari and Magdalena Moczała-Dusanowska and Christoph Kohlberger and Santanu Manna and Sandra Stroj and Julia Freund and Xueyong Yuan and Christian Schneider and Miroslav Ježek and Sven Höfling and Francesco Basso Basset and Tobias Huber-Loyola and Armando Rastelli and Rinaldo Trotta},
journal= {arXiv preprint arXiv:2212.12506},
year = {2024}
}