Simple Closed-Form Solution to Predict Short-Range Surface Plasmons in Thin Films Bounded by Asymmetric Media and Its Application to Hole Arrays

Thin metallic films bounded by two dielectric media can support long- and short-range surface plasmon polaritons (SPPs). The dispersion relation associated with these hybrid modes is given by a complex transcendental equation that can only be solved numerically. In this paper, a simple approximate analytical solution for the short-range modes is derived. To validate the proposed analytical solution, short-range SPPs in a 2-D periodic array of small holes are studied and compared to full-wave simulations. The results prove a spectral response in excellent agreement.