Giant transmission and dissipation in perforated films mediated by surface phonon polaritons

We 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 $\epsilon_{\rm eff}(\omega)$ of the perforated film. The value of $\epsilon_{\rm eff}(\omega)$ 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 $\epsilon_{\rm eff}(\omega)$ strongly enough to cause giant transmission and absorption.