Interaction among plasmonic resonances in a gold film embedding a two-dimensional array of polymeric nanopillars

Nanostructured surfaces have proven to be effective in controlling the electric field distribution and triggering a series of interesting physical effects. In particular, ordered metallic lattices with a typical size of the same order of magnitude of the wavelength of the incident radiation exhibit extraordinary transmission and reflection properties and represent a sensitive tool to exploit surface plasmon resonance for sensing applications. We investigated, either by experimental structural and optical measurements or by modeling and calculations, samples consisting of a two-dimensional array of polymeric pillars embedded in a gold film. In particular, we analyzed the dependence of the plasmonic resonance on the pillar size. We showed that a peculiar interplay among localized modes and propagating surface plasmon polaritons exists for some selected conditions and affects the spectral distribution, lifetime, and field configuration of the plasmonic excitations. (C) 2012 Optical Society of America