2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/114446We experimentally and theoretically study electromagnetic properties of optically thin silicon carbide (SiC) membranes perforated by an array of sub-wavelength holes. Giant absorption and transmission is found using Fourier Transformed Infrared (FTIR) microscopy and explained by introducing a frequency-dependent effective permittivity $ε_{\rm eff}(ω)$ of the perforated film. The value of $ε_{\rm eff}(ω)$ is determined by the excitation of two distinct types of hole resonances: a delocalized slow surface polariton (SSP) whose frequency is largely determined by the array period, and a localized surface polariton (LSP) which corresponds to the resonances of an isolated hole. Only SSPs are shown to modify $ε_{\rm eff}(ω)$ strongly enough to cause giant transmission and absorption.11 pages, 4 figsOpticsComputational Physicstext