Resonances in Mie scattering by an inhomogeneous atomic cloud

TL;DR

This paper demonstrates that resonances in Mie scattering can be observed in dense cold atomic clouds with inhomogeneous density, showing regular oscillations in scattering and radiation pressure, bridging classical and quantum descriptions.

Contribution

It introduces a classical Mie scattering approach to inhomogeneous atomic clouds with parabolic density profiles, revealing observable resonances in cooperative scattering.

Findings

Resonances are observable by tuning laser frequency or atom number.

Density inhomogeneity leads to regular oscillations rather than complex peaks.

Resonances affect radiation pressure and cloud displacement.

Abstract

Despite the quantum nature of the process, collective scattering by dense cold samples of two-level atoms can be interpreted classically describing the sample as a macroscopic object with a complex refractive index. We demonstrate that resonances in Mie theory can be easily observable in the cooperative scattering by tuning the frequency of the incident laser field or the atomic number. The solution of the scattering problem is obtained for spherical atomic clouds who have the parabolic density characteristic of BECs, and the cooperative radiation pressure force calculated exhibits resonances in the cloud displacement for dense clouds. At odds from uniform clouds which show a complex structure including narrow peaks, these densities show resonances, yet only under the form of quite regular and contrasted oscillations.