Analysis of filter and waveguide effect based on the MIM nanodisk with a metallic block

Abstract

A novel and meaningful plasmonic filter based on the metal-insulator-metal (MIM) waveguides directly connected to a nanocavity with a metallic block is proposed and demonstrated numerically. By the effective index method and the resonant theory of disk-shaped nanocavity, we reveal that the resonant wavelengths can be simply tuned by adjusting the height of the block, which is in accordance with the results calculated by finite-difference time-domain (FDTD) simulations. We also rotate the metallic block to achieve two resonant modes. One mode shows a blue shift, and the other mode shows a red shift. It is shown that the proposed structure performs as a bend waveguide not a filter when the width of the block increases to hundreds of nanometers. The proposed structure will have significant potential applications in nanointegrated circuits for optical filtering and processing.