Enhanced optical transmission through planar metallic films via excitation of surface plasmons

A study on extraordinary optical transmission through planar metallic films closely coupled to periodic sub-wavelength structures is presented. The measured spectral positions of transmission maxima match well with the surface plasmon polariton (SPP) dispersion relations. The experimental results are further supported by rigorous coupled wave analysis (RCWA) simulations. The exceptional transmission is a result of coupling between the localized surface plasmon (LSP) mode existing in periodic sub-wavelength structures and the SPP modes on the planar metal films.