Resonant excitation of volume and surface fields on complex electrodynamic surfaces

Analytical, numerical, and experimental studies of volume and surface-field coupling in planar metal periodic surface lattice (PSL) structures superimposed on dielectric substrates with a metallic backing (PSLDM) are presented. We show the formation of frequency-locked PSLDM-coupled eigenmodes and unlocked surface-field resonances (PSL without substrate). These experimental observations are in excellent agreement with theoretical and numerical predictions. For the first time, the derivation of a field coupling coefficient α is demonstrated. By comparing theoretical and numerical dispersions, we obtain α. Detailed analysis of possible scattering mechanisms and dispersive behavior in subwavelength "effective metadielectric" PSLs is shown. The theory and measurements presented in this paper are applicable over a broad frequency range from optical frequencies to THz and are fundamental to the innovation of high-power short-wavelength sources, solar cells, and alternative subwavelength absorbers.