Tunable band-stop plasmonic filter based on square ring resonators in a metal-insulator-metal structure

Abstract

A novel high-performance plasmonic filter based on a metal–insulator–metal structure is analysed for band-rejection applications. A square ring is used in proximity to the waveguide in order to resonate with some transmitted wavelengths and drop them to prevent from propagation towards the output. The effect of the structural parameters of square ring resonator is studied deploying the finite difference time domain method and the possibility of tuning the rejected wavelength is investigated in detail. The simulation results demonstrate that the rejected wavelength has a red-shift with increase in the size of the ring’s dimensions. A further study is carried out considering narrowing the bandwidth. To improve the quality factor of the proposed filter, a small ring within the resonator is introduced that considerably decreases the bandwidth of the peak with respect to its central wavelength.

Keywords:

• Plasmonic filter
• metal–insulator–metal
• ring resonator
• narrow bandwidth