Classification of bianisotropic metasurfaces from reflectance and transmittance measurements

TL;DR

This paper presents a method to classify reciprocal bianisotropic metasurfaces using reflection and transmission measurements, providing experimental guidelines and clarifying common confusions in metasurface classification.

Contribution

It introduces a systematic approach to classify metasurfaces based on scattering parameters and polarization, clarifying the limitations of measurement-based inference.

Findings

Classification of metasurfaces into isotropic, anisotropic, bi-isotropic, and bianisotropic categories.

Guidelines for experimental identification of metasurface properties.

Clarification of misconceptions in polarization-based classification methods.

Abstract

Upon using fundamental electromagnetic properties of metasurfaces we build a platform to classify reciprocal bianisotropic metasurfaces from typical experimental measurements and determine isotropic, anisotropic, bi-isotropic (chiral), and bianisotropic (so-called omega) properties. We provide experimental guidelines to identify each class by measuring macroscopic scattering parameters, i.e., reflection and transmission coefficients upon plane wave illumination with linear and/or circular polarization. We explicitly provide a recipe of what metasurface properties can and cannot be inferred by means of chosen polarization, reflection, and transmission properties. We also clarify common confusions in the classification of anisotropic versus chiral metasurfaces based on circular dichroism measurements presented in the recent literature.