Hong-Ou-Mandel interference between triggered and heralded single photons from separate atomic systems

TL;DR

This paper demonstrates high-visibility Hong-Ou-Mandel interference between single photons generated from two distinct atomic systems, showcasing their compatibility for quantum interfaces without spectral filtering.

Contribution

It reports the first interference between photons from scattering by a single atom and four-wave mixing in cold atoms, advancing hybrid quantum system integration.

Findings

Visibility of 62% without filtering

Corrected visibility of 93% after accidental coincidence correction

Proof of compatibility between different photon sources

Abstract

We present Hong-Ou-Mandel interference of single photons generated via two different physical processes by two independent atomic systems: scattering by a single atom, and parametric generation via four-wave mixing in a cloud of cold atoms. Without any spectral filtering, we observe a visibility of V=62$\pm$4%. After correcting for accidental coincidences, we obtain V=93$\pm$6%. The observed interference demonstrates the compatibility of the two sources, forming the basis for an efficient quantum interface between different physical systems.