Multiple surface plasmon polaritons modes on thin silver film controlled by a two-dimensional lattice of silver nanodimers

摘要

We study the optical resonant spectrum of a two-dimensional periodic array of silver nanodimers on a thin silver film using multiple scattering formalism. The excited multiple plasmonic modes on two interfaces of the silver film reveal that the dispersion relationships of surface plasmon polaritons on metallic film are modified by doubly periodic lattice due to the fact that wave vectors matching conditions are satisfied. Moreover, we demonstrate that the plasmonic modes are directly controlled by the thickness of silver film, as well as the gap between nanodimer array and silver film. These effects provide novel high-efficient and steady way for excitation in future plasmonic nanodevices.