Photon-pair sources are widely used in quantum optics and quantum information experiments. Despite their broad deployment, there has not yet been an on-demand implementation with efficient into-fiber photon generation and high single-photon purity. Here we report on such a source based on a single atom with three energy levels in ladder configuration and coupled to two optical fiber cavities. We efficiently generate photon pairs with in-fiber emission efficiency of ηpair=16(1)% and study their temporal correlation properties. We simulate theoretically a regime with strong atom-cavity coupling and find that photons are directly emitted from the ground state, i.e. without atomic population in any intermediate state. We propose a scenario to observe such a double-vacuum-stimulated effect experimentally.
@article{arxiv.2501.01891,
title = {Two-cavity-mediated photon-pair emission by one atom},
author = {Gianvito Chiarella and Tobias Frank and Pau Farrera and Gerhard Rempe},
journal= {arXiv preprint arXiv:2501.01891},
year = {2025}
}