Beam engineering for selective and enhanced coupling to multipolar resonances

TL;DR

This paper introduces an analytical method to engineer optical beams for selective excitation of specific multipolar resonances in nanoparticles, enabling precise control over light-matter interactions in metamaterials.

Contribution

It develops a novel analytical approach to manipulate multipolar resonances in nanoparticles through beam engineering, advancing the control of light-matter interactions.

Findings

Demonstrated selective excitation of a longitudinal quadrupole mode

Showed manipulation of scattering properties by varying illumination

Provided a foundation for targeted multipolar resonance control

Abstract

Multipolar electromagnetic phenomena in sub-wavelength resonators are at the heart of metamaterial science and technology. In this letter, we demonstrate selective and enhanced coupling to specific multipole resonances via beam engineering. We first derive an analytical method for determining the scattering and absorption of spherical nanoparticles (NPs) that depends only on the local electromagnetic field quantities within an inhomogeneous beam. Using this analytical technique, we demonstrate the ability to drastically manipulate the scattering properties of a spherical NP by varying illumination properties and demonstrate the excitation of a longitudinal quadrupole mode that cannot be accessed with conventional illumination. This work enhances the understanding of fundamental light-matter interactions in metamaterials, and lays the foundation for researchers to identify, quantify, and manipulate multipolar light-matter interactions through optical beam engineering.