Deterministic free-space source of single photons using Rydberg atoms

TL;DR

This paper presents a deterministic free-space single-photon source using Rydberg atoms, which does not depend on cavity coupling or Rydberg blockade, enabling efficient and well-defined photon emission.

Contribution

The authors introduce a novel free-space scheme for single-photon generation utilizing Rydberg atoms and adiabatic passage, avoiding the need for cavity coupling or Rydberg blockade.

Findings

Efficient generation of single photons in free space.

No reliance on cavity or Rydberg blockade.

Produces well-defined spatiotemporal photon modes.

Abstract

We propose an efficient free-space scheme to create single photons in a well-defined spatiotemporal mode. To that end, we first prepare a single source atom in an excited Rydberg state. The source atom interacts with a large ensemble of ground-state atoms via a laser-mediated dipole-dipole exchange interaction. Using an adiabatic passage with a chirped laser pulse, we produce a spatially extended spin wave of a single Rydberg excitation in the ensemble, accompanied by the transition of the source atom to another Rydberg state. The collective atomic excitation can then be converted to a propagating optical photon via a coherent coupling field. In contrast to previous approaches, our single-photon source does not rely on the strong coupling of a single emitter to a resonant cavity, nor does it require the heralding of collective excitation or complete Rydberg blockade of multiple excitations in the atomic ensemble.