Characterization of Surface Electromagnetic Waves and Scattering on Infrared Metamaterial Absorbers

TL;DR

This study provides a comprehensive experimental and computational analysis of light interactions on infrared metamaterial absorbers, highlighting the roles of scattering and surface electromagnetic waves in absorption.

Contribution

It is the first to fully characterize all light matter interactions on infrared MMA surfaces through combined experimental and computational methods.

Findings

Diffuse scattering is negligible for wavelengths longer than the unit cell period.

Surface electromagnetic waves are generated at the operational wavelength for TM polarization.

Surface waves contribute to the angular dependence of absorption.

Abstract

We report, for the first time, a full experimental and computational investigation of all possible light matter interactions on the surface of an infrared metamaterial absorber (MMA). Two channels of energy dissipation - diffuse scattering and generation of surface electromagnetic waves - are quantified in terms of their impact on specular absorption. The diffuse scattering is found to play a negligible roll in the absorption process, at least for wavelengths greater than the periodicity of unit cell. In contrast, surface electromagnetic waves are found to be generated for transverse magnetic (TM) polarized light at the operational wavelength of the MMA, i.e. \lambda_0, and shorter wavelengths. Our computational results indicate that the highly lossy surface electromagnetic wave generated at \lambda_0 is responsible for the good angular dependence of absorption in TM polarization. Experimental results are supported by full wave three dimensional electromagnetic and eigenmode simulations.