Non-specular reflection by a planar resonant metasurface

TL;DR

This paper demonstrates a novel metasurface design that achieves strong, controllable non-specular reflection of light across various directions and polarizations, using silicon nanodisks on a silica-on-metal substrate.

Contribution

It introduces a double-ray scattering scenario enabling non-specular reflection and provides conditions for implementing an autocollimation scheme with tunable frequency bandwidth.

Findings

Achieved low-loss non-specular reflection for any incident angle and polarization.

Controlled the non-specular reflection by adjusting substrate thickness and incident parameters.

Numerical simulations confirm the feasibility of the proposed metasurface design.

Abstract

An uncommon double-ray scenario of light resonant scattering by a periodic metasurface is proposed to provide strong non-specular reflection. The metasurface is constracted as an array of silicon nanodisks placed on thin silica-on-metal substrate. A low-lossy non-specular resonant reflection for any direction and any polarization of incident wave is revealed by a numerical simulation of light scattering. The conditions for the implementation of an autocollimation scheme of scattering and the observation of non-specular reflected ray that does not lie in the incidence plane are worked out. It is shown that the change of dielectric substrate thickness may be applied to set the width of frequency band of non-specular reflection. The light intensity related to the specular and non-specular reflected ray can be controlled by changing the angle of incidence or by the polarization of incident wave.