Experimental evidence of total absorption by a thin absorbing layer deposited on a patterned metallic surface

TL;DR

This paper demonstrates experimentally that a thin dielectric layer on a patterned metallic surface can achieve total absorption of P-polarized waves, confirming theoretical predictions and exploring various parameters affecting absorption.

Contribution

It provides the first experimental validation of total absorption in a metal-dielectric metasurface as previously theorized, with detailed characterization of parameter effects.

Findings

Total absorption achieved at low frequencies for P-polarized waves.

Experimental results match numerical simulations closely.

Absorption peak varies with dielectric thickness, cavity length, and incidence angle.

Abstract

This work presents the experimental demonstration of total absorption by a metal-dielectric metasurface. Following the theoretical proposal [A. D\'iaz-Rubio et al. Phys. Rev. B 89, 245123 (2014)], we fabricated a metasurface consisting of a low absorbing dielectric layer (made of FR4) deposited on top of a metallic surface patterned with a square distribution of coaxial cavities. For P-polarized waves, it is observed a low frequency peak with perfect absorption. The behavior of this peak has been experimentally characterized for different dielectric layer thicknesses, coaxial cavity lengths and incidence angles. The experimental results are in excellent agreement with numerical simulation and support the previous theoretical findings.