Direct dark mode excitation by symmetry matching of a single-particle based metasurface

TL;DR

This paper demonstrates a symmetry-based mechanism for directly exciting dark modes in single-particle metasurfaces, offering a robust and fabrication-friendly approach for optical nanostructure design.

Contribution

It introduces a novel symmetry matching method for dark mode excitation that does not rely on near-field coupling, enhancing design robustness.

Findings

Efficient magnetic dipolar mode excitation observed

Dark mode excitation is symmetry-dependent, not coupling-dependent

Approach simplifies fabrication and improves robustness

Abstract

This paper makes evidence for direct dark mode excitation mechanism in a metasurface structure. The dark mode excitation mechanism is entirely determined by structures' symmetry and does not depend on near-field coupling between elements. In our examples, we consider single element based metasurface composed of two V antennas connected in an anti-symmetric arrangement. Both experimental and modeling results show an efficient excitation of magnetic dipolar mode in such structures. The direct dark mode excitation mechanism provides a design that is more robust with respect to technology imperfections. The considered approach opens promising perspectives for new type of nanostructure designs and greatly relaxes fabrication constraints for the optical domain.