Simulation of an aperture in the thick metallic screen that gives high intensity and small spot size using surface plasmon polariton

The optical wave behaviour around a subwavelength aperture in a thick metallic screen is examined through three-dimensional computer simulation. Treating the metallic screen as a dielectric slab with complex-valued permittivity, it is possible to design an aperture that simultaneously provides high intensity and small spot size through the excitation of surface plasmon polaritons on the side walls of the aperture.