An integrated atom-photon junction

TL;DR

This paper demonstrates a photonic chip with microscopic atom-photon junctions, enabling sensitive atomic detection and light probing, paving the way for integrated quantum information processing devices.

Contribution

It introduces a novel integrated chip with multiple atom-photon junctions, combining cold atoms with photonic circuits for enhanced quantum sensing and information processing.

Findings

Single atom detection via light absorption at junctions

Atoms used to probe light intensity and polarization

Device enables interconnected atom-photon circuits

Abstract

Photonic chips that integrate guides, switches, gratings and other components, process vast amounts of information rapidly on a single device. A new branch of this technology becomes possible if the light is coupled to cold atoms in a junction of small enough cross section, so that small numbers of photons interact appreciably with the atoms. Cold atoms are among the most sensitive of metrological tools and their quantum nature also provides a basis for new information processing methods. Here we demonstrate a photonic chip which provides multiple microscopic junctions between atoms and photons. We use the absorption of light at a junction to reveal the presence of one atom on average. Conversely, we use the atoms to probe the intensity and polarisation of the light. Our device paves the way for a new type of chip with interconnected circuits of atoms and photons.