A band-pass plasmonic filter with dual-square ring resonator

摘要

In this paper, we show the simulation of a plasmonic band-pass filter which consists of two surface plasmon polaritons (SPPs) waveguides and a resonator in metal–insulator–metal (MIM) structure. The resonator is formed by two square rings and a patch between them. The patch is a tiny rectangle cavity in order to transfer the SPPs from one ring to the other. The finite element method (FEM) method is employed in simulation. The results show that the dual-ring resonator performs better than a single ring does. The 3 dB bandwidth near the peak wavelength λ = 1054 nm is merely 31.7 nm. The resonant wavelength can be shifted by changing the side length of the square ring. This narrow band-pass filter is easy to fabricate and has potential applications in future integrated optical circuits.