Towards an optical far-field measurement of higher-order multipole contributions to the scattering response of nanoparticles

TL;DR

This paper introduces an all-optical method for decomposing the multipolar contributions of nanoparticle Eigenmodes using tailored cylindrical vector beams, enabling detailed analysis of higher-order modes through 2D intensity mapping.

Contribution

It presents a novel optical technique for multipolar decomposition of nanoparticle Eigenmodes, capturing higher-order contributions via scanning intensity maps.

Findings

Successful experimental decomposition of Eigenmodes.

Detection of higher-order multipolar contributions.

Enhanced understanding of nanoparticle scattering responses.

Abstract

We experimentally show an all-optical multipolar decomposition of the lowest-order Eigenmodes of a single gold nanoprism using azimuthally and radially polarized cylindrical vector beams. By scanning the particle through these tailored field distributions, the multipolar character of the Eigenmodes gets encoded into 2D-scanning intensity maps even for higher-order contributions to the Eigenmode that are too weak to be discerned in the direct far-field scattering response. This method enables a detailed optical mode analysis of individual nanoparticles.