Wavelength division multiplexer of surface plasmon polaritons using dual-periodical arranged metal gap waveguide

we investigate the propagation and scattering of surface plasmon polaritons (SPPs) in a dual-periodical metal heterowaveguide based on the transfer matrix method and the finite-difference time-domain analysis (FDTD). In this structure, the resonance transmission mode with high with high-quality factors can be generated. By adjusting the structure parameters, center frequency, frequency interval and number of the modes can be flexibly tuned. The numerical simulation agrees well with the theoretical predication. Our results can be implied for the SPP-based wavelength division multiplexers and multi-channel light emitters. The structure can be applied to the multi-wavelength filters.