Plasmonic multimode waveguides with transversely structured core.

We analyze the propagation of surface plasmons in metallic multimode waveguides that consist of alternating stripes of different metals in the transverse direction and that are homogeneous in the longitudinal direction. The purpose of structuring the waveguide in the transverse direction is to take advantage of the different attenuation and propagation constants for different metals. Here, in particular, alternating stripes of Ag and Au are considered. This allows one to influence the modal spectrum. We consider two different, well-defined waveguide configurations. For these, the propagating plasmonic modes are calculated. Based on the numerical simulations, we discuss the attenuation and propagation behavior and show the resulting eigenmodes for different values of the structural parameters, i.e., widths and thicknesses.

Analysis of the self-imaging effect in plasmonic multimode waveguides.

We present studies on the propagation of plasmon waves in metallic multimode waveguides surrounded by a dielectric medium. The permittivity of the metal was determined by a Drude model. The propagation was simulated by the method of lines. The propagating field exhibited the well-known self-imaging phenomenon known as the Talbot effect. The metallic waveguides are lossy. The influence of various parameters on the losses was examined. By a suitable choice of parameters, propagation distances of several Talbot periods are possible. Our investigation also includes simulations for the propagation of eigenmodes of the waveguides and results for the calculation of the effective index.