Polarization-dependent plasmonic color filter based on different sizes nanodisk arrays built-up structure

The plasmonic color filter with a suitable bandwidth, high transmittance is usually regarded as an essential optical element for a variety of utilization. Here, we propose an ultra-thin plasmonic color filter based on a substrate free dielectric film waveguide composed of two sizes of metal-disk. The proposed plasmonic filter operates through the hybrid role of surface plasmon polariton (SPP) mode, the localized Fabry-Perot resonance, and waveguide mode. The filter consists of a waveguide layer (Si₃N₄), a buffer layer (MgF₂) and a nanodisk (Al). This paper uses the finite difference time domain (FDTD) method. The boundary condition is the boundary condition of the perfectly matched layer(PML) with anisotropy in Y direction, and the periodic boundary condition is selected in X and Z directions. In this paper, the influence of the thickness of the waveguide layer, the thickness of the buffer layer and the nanodisk period on the transmission spectrum is discussed, and the polarization-dependence of the filter is also discussed. The results demonstrate that the filter has more than 80% transmittance and is related to polarization and can be implemented to color display and integrated optoelectronic devices.