Interfacing light and single atoms with a lens

TL;DR

This paper investigates the interaction between single atoms and focused light beams, developing models to accurately describe scattering ratios and comparing them with experimental data to improve understanding of light-matter coupling.

Contribution

It introduces a refined interference-based model for atom-light scattering that corrects unphysical predictions of earlier models in strong focusing regimes.

Findings

Refined model aligns well with experimental extinction measurements.

Scattering ratios are accurately predicted across various focusing strengths.

Interference effects are crucial for understanding atom-light interactions in focused beams.

Abstract

We characterize the interaction between a single atom or similar microscopic system and a light field via the scattering ratio. For that, we first derive the electrical field in a strongly focused Gaussian light beam, and then consider the atomic response. Following the simple scattering model, the fraction of scattered optical power for a weak coherent probe field leads to unphysical scattering ratios above 1 in the strong focusing regime. A refined model considering interference between exciting and scattered field into finite-sized detectors or optical fibers is presented, and compared to experimental extinction measurements for various focusing strengths.