Multilayer metamaterial absorbers inspired by perfectly matched layers

TL;DR

This paper introduces multilayer metamaterial absorbers inspired by perfectly matched layers, using effective medium theory to create practical electromagnetic absorbers with good reflection and absorption properties.

Contribution

It presents a novel effective medium PML (EM-PML) approach for designing multilayer absorbers that mimic PML behavior in real materials.

Findings

Layered absorbers closely match PML reflection spectra.

Effective medium approximation remains functional without gain and magnetic properties.

Cylindrical core-shell nanostructures exhibit strong absorption and reflection.

Abstract

We derive periodic multilayer absorbers with effective uniaxial properties similar to perfectly matched layers (PML). This approximate representation of PML is based on the effective medium theory and we call it an effective medium PML (EM-PML). We compare the spatial reflection spectrum of the layered absorbers to that of a PML material and demonstrate that after neglecting gain and magnetic properties, the absorber remains functional. This opens a route to create electromagnetic absorbers for real and not only numerical applications and as an example we introduce a layered absorber for the wavelength of $8$~$\mu$m made of SiO$_2$ and NaCl. We also show that similar cylindrical core-shell nanostructures derived from flat multilayers also exhibit very good absorptive and reflective properties despite the different geometry.