Plasmon flow control at gap waveguide junctions using square ring resonators

Abstract

A compact add-drop coupler with square ring resonator (SRR) in gap plasmon waveguide is studied. It is shown that there exist both travelling-wave and standing-wave resonant modes in the resonator due to the influence of the four corners in the square ring. Based on SRR, a new type of two-dimensional plasmonic L-shaped bend is proposed. The compact geometry and high add-drop efficiency of the proposed structure enable the realization of flexible flow control at waveguide junctions, e.g. T-splitter and waveguide cross intersections, in nano scale. The optical field propagation patterns in the gap waveguide junctions equipped with SRRs are investigated by the finite-difference time-domain method.