Numerical study of plasmonic filter based on metal-insulator-metal waveguide

Abstract

A novel nanometeric plasmonic filter comprised of double-sided eight stub resonators side-coupled with a metal-isolator-metal waveguide is proposed and demonstrated numerically by the finite element method. The numerical results show that the four transmittance peaks in a transmission spectrum range from 400 nm to 2000 nm can be achieved due to the electromagnetically-induced-transparency-like spectral responses between every two adjacent stub resonators with detuned cavity length. Based on the magnetic field distributions from the two dimensional model, the physical origins of transmittance peaks and dips are clarified by phase analysis of Fabry-Perot resonance effect. In addition, the central wavelengths of transmittance peaks can be tuned by adjusting the cavity length of each stub resonator, which means the waveguide filter could be utilized to develop ultracompact and tunable narrowband photonic filters for high integration.