Beam filter and splitter based on surface plasmon propagation in ring metal heterowaveguide

Abstract

Surface plasmon polaritons (SPPs) beam filter (BF) and beam splitter (BS) constructed using metal heterostructures are proposed and demonstrated numerically. Both structures have a ring metal heterowaveguide, which is constructed by a metal cylinder and a ring dielectric cladding. The two-dimensional finite-difference time-domain (2D-FDTD) method is employed to study the properties of the proposed BF and BS, and the results show that SPPs can effectively propagate on bended plasmonic waveguides with dielectric claddings. By introducing dielectric and plasmonic waveguides on both sides of the resonant ring, SPPs can be efficiently excited at the output of the waveguide ring resonator (WRR) through mode coupling. The planar metal heterostructures provide a way for constructing various nanoscale counterparts of conventional planar integrated devices such as filters, splitters, resonators, sensors, optical switches, and so on.