Multiple ultra-narrow band-stop filters based on MIM plasmonic waveguide with nanoring cavities

Abstract

In this work, multiple ultra-narrow band-stop filters based on metal–insulator–metal (MIM) plasmonic waveguide filters with high efficiency are designed and analyzed numerically. The relationship between incident radiation and transmission spectra is investigated between 0.45 μm and 1.5 μm in the electromagnetic spectrum by finite-difference time-domain (FDTD) method. The designed structures have a bus waveguide coupled with nanoring cavity resonators of different sizes. Minimum transmission is 1.3% at 622 nm. The full width at half maximum (FWHM) is 8.64 nm and the quality factor is obtained as 72.33 in this wavelength. The highest quality factor is 185.48 and the lowest FWHM is 4.2 nm at 779 nm. The designed waveguide-based filters can be used for integrated optical devices from visible to near-infrared regimes.