Plasmonic nanostructures with waveguiding effect

A mutual coupling of a surface plasmon polariton (SPP) with an optical mode excited in a planar waveguide (WG) is discussed. A planar layered structure is studied consisting of a coupling prism, an Au film and a high-index interlayer for SPPs generation, and a dielectric waveguide composed of a ferromagnetic garnet on a (CaMgZr)-doped gallium–gadolinium garnet substrate (GGG) separated by an air gap. The dependence of coupling resonances on the gap thickness and the interlayer refractive index is analyzed to obtain an optimal field intensity enhancement for future designs of plasmonic and magneto-plasmonic sensing elements.