Influence of diffusion of atoms on the dark resonance lineshape in spatially bounded laser fields

TL;DR

This paper develops a diffusion model to explain the diffusion-induced Ramsey narrowing effect in atoms within buffer-gas cells, analyzing how atomic diffusion influences the shape of dark resonance lines under various cell geometries.

Contribution

It introduces a new diffusion equation for atomic coherence in a three-level system, linking atomic motion to dark resonance lineshape in laser fields.

Findings

The model explains the dependence of resonance lineshape on two-photon detuning.

Different cell geometries significantly affect the resonance lineshape.

The approach enhances understanding of atom-light interactions in confined geometries.

Abstract

We propose a diffusion model for the recently discovered diffusion-induced Ramsey narrowing arising when atoms diffuse in a buffer-gas cell in the laser radiation field. The diffusion equation for the coherence of metastable states coupled with an excited state by laser radiation of different frequencies in a three-level scheme of the atom-field interaction is obtained in the strong-collision approximation. The dependence of the shape of an absorption line near the transmission maximum of one of the frequencies on the two-photon resonance detuning for various geometries of the cell is investigated.