Optical Reflectivity of Asymmetric Dielectric–Metal–Dielectric Planar Structures

We report simulations and experimental results on the incidence-angle dependence of the optical reflectivity of asymmetric dielectric–metal–dielectric planar structures. Transfer-matrix method and 2-D finite-element analysis revealed the presence of multiple resonances that were attributed to the surface plasmon (SP) polariton mode at the metal–dielectric interfaces and guided-wave polariton modes within the asymmetric dielectric–metal–dielectric waveguide. The number of guided-wave polariton resonances scale with the thickness of the dielectric guiding layer while the SP resonance remained essentially unaltered. These findings were validated through reflectivity measurements on sapphire–metal–polymer structures.