Excitation of multiple surface-plasmon-polariton waves guided by the periodically corrugated interface of a metal and a periodic multilayered isotropic dielectric material

Abstract

The excitation of multiple surface-plasmon-polariton (SPP) waves guided by the periodically corrugated interface of a homogeneous metal and a periodic multilayered isotropic dielectric (PMLID) material was studied theoretically. The solution of the underlying canonical boundary-value problem (with a planar interface) indicates that multiple SPP waves of different polarization states, phase speeds, and attenuation rates can be guided by the periodically corrugated interface. Accordingly, the boundary-value problem was formulated using rigorous coupled-wave analysis and solved using a numerically stable algorithm. A linearly polarized plane wave was considered obliquely incident on a PMLID material of finite thickness and backed by a metallic surface-relief grating. The total reflectance, total transmittance, and the absorptance were calculated as functions of the incidence angle for different numbers of unit cells in the PMLID material of fixed period. The excitation of SPP waves was indicated by those peaks in the absorptance curves that were independent of the number of unit cells, and these peaks were also correlated with the solutions of a dispersion equation obtained from the canonical boundary-value problem.