Double and triple-wavelength plasmonic demultiplexers based on improved circular nanodisk resonators

Abstract

Plasmonic demultiplexers using improved circular nanodisk resonators (CNRs) and metal-insulator-metal waveguides have been designed. The proposed structures use air and silver as insulator and metal layers, respectively. The relative permittivity of silver has been characterized by Drude, Palik, and Drude–Lorentz models in our finite-difference time-domain simulations. To obtain demultiplexers, first two filters based on improved CNRs are designed. One of the most outstanding features of a CNR is that the resonance wavelength can be tuned by changing its radius. It is shown that increasing the CNRs radii for the single-mode bandpass filter increases the resonance wavelength, linearly. Accordingly, double and triple-wavelength demultiplexers (DeMuxes) have been proposed for the wavelength range of 600 to 2000 nm. Due to their small area, the proposed demultiplexers can be applied in integrated optical circuits for optical communication purposes.