Theory of metasurface based perfect absorbers

TL;DR

This paper provides a theoretical review of metasurface-based perfect absorbers, analyzing their absorption limits, scattering, and extinction, and compares different designs like Huygens metasurfaces and Salisbury absorbers.

Contribution

It offers an analytical framework for understanding the maximum absorption limits and analyzes two main metasurface absorber designs with numerical examples.

Findings

Maximum absorption limits for resonant dipole metasurfaces

Comparison of Huygens and Salisbury absorber designs

Numerical validation of analytical results

Abstract

Based on an analytic approach, we present a theoretical review on the absorption, scattering, and extinction of both dipole scatterers and regular arrays composed of such scatterers i.e., metasurfaces. Besides offering a tutorial by outlining the maximum absorption limit for electrically/magnetically resonant dipole particles/metasurfaces, we give an educative analytical approach to their analysis. Moreover, we put forward the analysis of two known alternatives in providing perfect absorbers out of electrically and or magnetically resonant metasurfaces; one is based on the simultaneous presence of both electric and magnetic responses in so called Huygens metasurfaces while the other is established upon the presence of a back reflector in so called Salisbury absorbers. Our work is supported by several numerical examples to clarify the discussions in each stage.