Interference and dynamics of light from a distance-controlled atom pair in an optical cavity

TL;DR

This study demonstrates control over light interference from a pair of atoms in an optical cavity, revealing phenomena like saturation and photon bunching, with implications for quantum information and fundamental light-matter interaction research.

Contribution

It introduces a scalable experimental platform combining atom localization, single-site imaging, and optical resonators to observe interference effects in atom-photon systems.

Findings

Resonator-induced saturation of resonance fluorescence.

Observation of nonzero emission with photon bunching.

Control over interference effects in atom-cavity systems.

Abstract

Interference is central to quantum physics and occurs when indistinguishable paths exist, like in a double-slit experiment. Replacing the two slits with two single atoms introduces optical non-linearities for which nontrivial interference phenomena are predicted. Their observation, however, has been hampered by difficulties in preparing the required atomic distribution, controlling the optical phases and detecting the faint light. Here we overcome all of these experimental challenges by combining an optical lattice for atom localisation, an imaging system with single-site resolution, and an optical resonator for light steering. We observe resonator-induced saturation of resonance fluorescence for constructive interference of the scattered light and nonzero emission with huge photon bunching for destructive interference. The latter is explained by atomic saturation and photon pair generation. Our experimental setting is scalable and allows one to realize the Tavis-Cummings model for any number of atoms and photons, explore fundamental aspects of light-matter interaction, and implement new quantum information processing protocols.