Characterization of the optical modes in 3D-periodic arrays of metallic nanospheres

Complex optical modes in 3D-periodic arrays of metallic nanospheres are analyzed at optical frequencies for both longitudinal and transversal (with respect to the mode traveling direction) polarization states. Each nanosphere of the array is modeled to act as a single dipole by using the single dipole approximation approach, and the metal permittivity is described by the Drude model. Complex mode dispersion diagrams, the figure of merit and effective refractive index versus frequency are shown and compared with those obtained with Maxwell Garnett homogenization theory. Comparison with effective permittivity retrieved by scattering parameters of finite-thickness structures will be shown during the presentation.