Strong coupling between single atoms and non-transversal photons

TL;DR

This paper demonstrates that non-transversally polarised photons significantly alter the strong light-matter interaction with single atoms, advancing cavity quantum electrodynamics and enabling new quantum systems.

Contribution

It experimentally shows the impact of non-transversal polarisation on strong coupling between single atoms and photons in microresonators, a novel insight in light-matter interaction.

Findings

Non-transversal polarisation affects strong coupling physics.

Experimental coupling of rubidium atoms with non-transversal photons.

Implications for cavity quantum electrodynamics and quantum technologies.

Abstract

We investigate the interaction between single quantum emitters and non-transversally polarised photons for which the electric field vector amplitude has a significant component in the direction of propagation. Even though this situation seems to be at odds with the description of light as a transverse wave, it regularly occurs when interfacing or manipulating emitters with non-paraxial, guided, or evanescent light. Here, we couple single rubidium atoms to single photons which are confined in an optical microresonator by continuous total internal reflection. We experimentally show that the non-transversal polarisation decisively alters the physics of strong light--matter interaction. This effect has far-reaching and highly advantageous implications, which, e.g., significantly advance the field of cavity quantum electrodynamics with whispering-gallery-mode resonators. In particular, our finding allows us to experimentally realise a paradigmatic quantum system, which is ideally suited for basic studies and technological applications.