Two-photon gateway in one-atom cavity quantum electrodynamics

TL;DR

This paper demonstrates that a single atom in an optical cavity can act as a two-photon gateway, converting random photon streams into correlated pairs due to quantum anharmonicity, with potential for controlled photon interactions.

Contribution

It introduces the concept of a two-photon gateway using a single atom-cavity system, showing photon pair generation and correlation in a quantum electrodynamics setup.

Findings

Observation of photon pair emission in a single-atom cavity system

Transformation of random photon streams into correlated pairs

Potential for controlled two-photon interactions using one atom

Abstract

Single atoms absorb and emit light from a resonant laser beam photon by photon. We show that a single atom strongly coupled to an optical cavity can absorb and emit resonant photons in pairs. The effect is observed in a photon correlation experiment on the light transmitted through the cavity. We find that the atom-cavity system transforms a random stream of input photons into a correlated stream of output photons, thereby acting as a two-photon gateway. The phenomenon has its origin in the quantum anharmonicity of the energy structure of the atom-cavity system. Future applications could include the controlled interaction of two photons by means of one atom.