Multimodal Anti-Reflective Coatings for Perfecting Anomalous Reflection from Arbitrary Periodic Structures

TL;DR

This paper introduces a simple, modular dielectric coating approach that enables perfect anomalous reflection from arbitrary periodic structures, simplifying wave control without complex meta-atom design.

Contribution

The paper proposes a multimodal anti-reflective coating (MARC) that suppresses undesired modes and achieves perfect anomalous reflection using uniform dielectric layers, bypassing complex metasurface design.

Findings

The MARC effectively suppresses unwanted modes in various structures.

Experimental results confirm perfect anomalous reflection with MARC.

The approach is applicable across different physical domains.

Abstract

Metasurfaces possess vast wave-manipulation capabilities, including reflection and refraction of a plane wave into non-standard directions. This requires meticulously-designed sub-wavelength meta-atoms in each period of the metasurface which guarantee unitary coupling to the desired Floquet-Bloch mode or, equivalently, suppression of the coupling to other modes. Herein, we propose an entirely different scheme to achieve such suppression, alleviating the need to devise and realize such dense scrupulously-engineered polarizable particles. Extending the concept of anti-reflective coatings to enable simultaneous manipulation of multiple modes, we show theoretically and experimentally that a simple superstrate consisting of only several uniform dielectric layers can be modularly applied to \textit{aribtrary} periodic structures to yield perfect anomalous reflection. This multimodal anti-reflective coating (MARC), designed based on an analytical model, presents a conceptually and practically simpler paradigm for wave-control across a wide range of physical branches, from electromagnetics and acoustics to seismics and beyond.