Selective Excitation of Subwavelength Atomic Clouds

TL;DR

This paper demonstrates how subwavelength atomic clouds can be modeled as single scatterers with controllable scattering properties by selectively exciting multipole moments, enabling tailored light-matter interactions.

Contribution

It introduces a model linking coherent and incoherent scattering in atomic clouds via effective multipole moments and shows how to selectively excite these moments to control scattering behavior.

Findings

Atomic clouds can be modeled as single scatterers with multipole moments.

Selective excitation of multipole moments controls scattering properties.

The approach enables manipulation of cooperative shifts and radiation patterns.

Abstract

A dense cloud of atoms with randomly changing positions exhibits coherent and incoherent scattering. We show that an atomic cloud of subwavelength dimensions can be modeled as a single scatterer where both coherent and incoherent components of the scattered photons can be fully explained based on effective multipole moments. This model allows us to arrive at a relation between the coherent and incoherent components of scattering based on the conservation of energy. Furthermore, using superposition of four plane waves, we show that one can selectively excite different multipole moments and thus tailor the scattering of the atomic cloud to control the cooperative shift, resonance linewidth, and the radiation pattern. Our approach provides a new insight into the scattering phenomena in atomic ensembles and opens a pathway towards controlling scattering for applications such as generation and manipulation of single-photon states.