Planar metal heterostructures for nanoplasmonic waveguides

The authors propose and numerically demonstrate a planar metal heterostructure for guiding surface plasmon polaritons (SPPs). By the analysis of the effective index method and finite-difference time-domain numerical simulations, they reveal that the planar metal heterostructure created by inlaying a Ag film, on which SPPs show a lower phase velocity, into an Al film and coating them with a uniform dielectric layer can strongly confine SPPs in the Ag region of the waveguide with 171×33nm2 cross section and 1.76μm propagation length. The planar metal heterostructures provide a way for constructing various nanoscale counterparts of conventional planar integrated devices such as splitters, resonators, sensors, optical switches, logical circuit, etc.