Lenses as an Atom-Photon Interface: A Semiclassical Model

TL;DR

This paper develops a semiclassical model to describe the interaction between a focused light field and an atom at arbitrary positions, accounting for thermal fluctuations, and explains experimental extinction data.

Contribution

It introduces a formalism for modeling atom-light interactions with focused beams considering atomic position fluctuations.

Findings

Thermal fluctuations explain observed extinction data.

The model accurately describes atom-light interaction beyond ideal focal conditions.

Provides a framework for analyzing focused light and atom systems at finite temperatures.

Abstract

Strong interaction between the light field and an atom is often achieved with cavities. Recent experiments have used a different configuration: a propagating light field is strongly focused using a system of lenses, the atom being supposed to sit at the focal position. In reality, this last condition holds only up to some approximation; in particular, at any finite temperature, the atom position fluctuates. We present a formalism that describes the focalized field and the atom sitting at an arbitrary position. As a first application, we show that thermal fluctuations do account for the extinction data reported in M. K. Tey et al., Nature Physics 4, 924 (2008).