Fabrication of plasmonic waveguides for device applications

We report on experimental realization of different metal-insulator geometries that are used as plasmonic waveguides guiding electromagnetic radiation along metal-dielectric interfaces via excitation of surface plasmon polaritons (SPPs). Three configurations are considered: metal strips, symmetric nanowires and nanowire pairs embedded in a dielectric, and metal V-shaped grooves. Planar plasmonic waveguides based on nm-thin and pm-wide gold strips embedded in a polymer that support propagation of long-range SPPs are shown to constitute an alternative for integrated optical circuits. Using uniform and thickness-modulated gold strips different waveguide components including reflecting gratings can be realized. For applications where polarization is random or changing, metal nanowire waveguides are shown to be suitable candidates for efficient guiding of arbitrary polarized light. Plasmonic waveguides based on metal V-grooves that offer subwavelength confinement are also considered. We focus on recent advances in manufacturing of nanostructured metal strips and metal V-grooves using combined UV, electron-beam and nanoimprint lithography.