Dielectric stripes on gold as surface plasmon waveguides

We report on surface plasmon polariton (SPP) waveguiding by SiO2 stripes on gold thin films. Compared to other SPP waveguide schemes, these systems provide relatively large effective refractive indices which can be described by the effective index method. By leakage radiation and near-field optical microscopy, we observe directly multimode and monomode behavior in straight SPP waveguides of different widths. Furthermore, we demonstrate waveguide bends and cross-talk free propagation across waveguide crossings.