All-dielectric resonant metasurfaces with a strong toroidal response

TL;DR

This paper presents a method to design all-dielectric metasurfaces with a strong toroidal electromagnetic response by arranging nanodisks into asymmetric clusters, linking the response to symmetry-breaking and trapped modes.

Contribution

It introduces a novel design of all-dielectric metasurfaces with enhanced toroidal response through asymmetric nanocluster arrangements, advancing metasurface engineering.

Findings

Strong axial toroidal response achieved

Correlation between asymmetry and response established

Design principles for symmetry-breaking in metasurfaces

Abstract

We demonstrate how to create all-dielectric metasurfaces with a strong toroidal response by arranging two types of nanodisks into asymmetric quadrumer clusters. We demonstrate that a strong axial toroidal response of the metasurface is related to conditions of the trapped (dark) mode that is excited due the symmetry breaking in the cluster. We study the correlation between the toroidal response and asymmetry in the metasurface and nanocluster geometries, which appears from the different diameters of nanodisks or notches introduced into the nanodisks.