Wedge Angle-Dependent Propagation Characteristics of Two Coupled Semi-Infinite Au Rib Nanoplasmonic Waveguides

The wedge angle-dependent propagation characteristics of two coupled semi-infinite Au rib nanoplasmonic waveguides are investigated using the three-dimensional finite-difference time-domain (3D FDTD) method with the fast Fourier transform and curve fitting techniques. The simulation results show that the propagation loss and modal index of the fundamental mode are closely related to the field distribution of the supermode which can be manipulated by varying the wedge angle from 75° to 100°. Understanding of the nanostructure-induced enhancement of the propagation characteristics of nanoplasmonic waveguides helps us find the best way to optimize the metallic waveguiding structures.