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

Power Loss Reduction of Angled Metallic Wedge Plasmonic Waveguides via the Interplay between Near-Field Optical Coupling and Modal Coupling

“…The metal is Au, Ag, Cu or Al. The used conditions (gird sizes and time step) in the FDTD simulations follow our previous report [22]. It is predicted that the optical modes and field distributions of the SPP waves are related to the wedge angle, which can be used to manipulate the power loss and modal index.…”

“…The modal index, power loss and modal field distribution of the CWP waveguide are calculated by using the finite-difference time-domain (FDTD) method, fast Fourier transform technique and curving fitting process [9,22]. To effectively excite the fundamental mode and higher order modes of the CWP waveguides, an electrical dipole is used to effectively excite the SPP waves supported in the CWP waveguides.…”

“…To effectively excite the fundamental mode and higher order modes of the CWP waveguides, an electrical dipole is used to effectively excite the SPP waves supported in the CWP waveguides. The perfectly matched layers (10 layers) [22] are used as the efficient absorbing boundaries in order to minimize the reflections from the outgoing electromagnetic waves at the six computational boundaries. The excitation wavelength of the electrical dipole is fixed at 1550 nm, which is widely used in the optical telecommunication wavelength range.…”

“…In this study, we found that the near-field optical coupling [22] and modal coupling both influence the spatial distortion of the modal field, which can be used to manipulate power loss of the CWP waveguide. Our simulation results show that the lowest power loss and modal index can be simultaneously obtained when the wedge angle of the CWP waveguide decreases from 90 • to 60 • .…”

“…Therefore, the weak and strong dielectric responses result in the long penetration depth in the dielectric and the short penetration depth in the metal, respectively. Fortunately, the effective dielectric responses in dielectric materials and metals can be manipulated via the near-field optical coupling, which results in the position-dependent wave impedance of the supported SPP wave at nanoscales and thereby influencing the light-material interaction strength (power loss) [22].…”