Perturbative approach for surface plasmon effects on flat interfaces periodically corrugated by subwavelength apertures

A perturbative approach for surface-plasmon-related effects encountered in metallo dielectric interfaces that incorporate periodic subwavelength defects with arbitrary shapes or materials is presented. It provides a simple insight into the physics of some important optical properties of these interfaces. We apply this understanding to one and two-dimensional metallic membranes perforated by subwavelength apertures and other related gratings geometries. The approach accounts quantitatively for the nearly null transmission of these membranes in the surface plasmon frequency band. It also predicts phenomena like an antisymmetric surface plasmon resonance for gratings with a vertical mirror symmetry at very small incidences and the possible absence of any reflection when outcoupling from an array of subwavelength slits into free space.