Surface modes on nanostructured metallic surfaces

Abstract : The dispersion properties of surface modes supported by metal/dielectric interfaces perforated by twodimensional arrays of subwavelength apertures are studied. An analytical surface-impedance model is derived. It provides closed-form expressions for the dispersion relation of surface modes and allows to take into account the aperture geometry and the dispersive and dissipative properties of the metal. The model predicts the dispersion relation and the mode lifetime, in quantitative agreement with fully vectorial computational results and with experimental data obtained at optical frequencies. The analysis reveals a double plasmonic band gap in the center of the Brillouin zone for a square array. It additionally clarifies the effects of various different geometrical and material parameters on the surface properties.