Design of High-Saturation Color Filter Models Based on Plasmonic Metasurfaces
Objective Color filters that reflect or transmit specific light wavelengths within the visible spectrum are extensively utilized in color printing,integrated displays,and image sensing.Traditional color filters,created by adopting the absorption properties of chemical pigments,exhibit low stability due to their sensitivity to ultraviolet radiation.Additionally,they often have problems such as large size and low resolution.However,the ongoing advancement of nanotechnology has paved the way for stable,high-resolution color control via color filters based on plasmon metasurface structures.These structures,composed of metal units in a large-area array,derive their optical response from the plasma resonance interaction between the metal and the dielectric surface.Meanwhile,constructing periodic plasmon metasurface arrays on the medium surface enables efficient transmission,thus producing ideal colors within the visible spectrum.Plasma color filters employ sub-wavelength-sized structural units,which leads to an ultra-thin volume that facilitates arrangement on high-precision and large-area arrays,thereby promoting the integration and miniaturization of display devices.Furthermore,adjusting the plasma's structural parameters can achieve exceptionally high spectral resolution.Methods We employ the finite element method for the numerical computation of the filter models.A unit structure of a color filter model is constructed in COMSOL Multiphysics software to facilitate the filtering effect simulation and analysis across the entire visible light spectrum.Results and Discussions A color filter model featuring a metal array/buffer medium/planar waveguide structure is developed.This model leverages surface plasmon-coupled dielectric waveguides excited by a cubic metal Al block array to facilitate color filtering within the visible light spectrum.By manipulating the filter's structural parameters,the resonance peak wavelength can be flexibly controlled to yield different structural colors.Additionally,various filter structural parameters are optimized to enhance the saturation of these colors.Precise adjustments to the metal array size,spacer layer thickness,and waveguide layer thickness lead to the successful optimization of the filtering model,producing high-saturation and high-quality structural colors in the 454 nm blue light band.Compared to others,this color filter model occupies less space and has higher color saturation.Conclusions We develop a color filter model based on plasmon metasurfaces.This model comprises a top-down arrangement of a metal Al metasurface array layer,a SiO2 dielectric interlayer,a Si3N4 waveguide layer,and a SiO2 substrate layer.Previous studies examine the transmission spectrum changes associated with different plasmon metasurface structures.Compared to the disk array and periodic pore structures,the cube metal block array structure of the plasma color filter model demonstrates superior transmittance,color saturation,and filtering characteristics in the blue light band.Electromagnetic field distribution simulations within the filter model at the resonance peak and zero transmittance reveal an uneven distribution,which is attributed to surface plasmons excited in the metal Al and guided mode resonance of the dielectric waveguide.Structural parameter adjustments lead to significant changes in the transmission spectrum and chromaticity coordinates.To design a color filter model with optimal filtering performance,we thoroughly examine the effects of various parameters on filtering performance and summarize patterns of their effects to identify the optimal performance parameters for various structures.By conducting simulation experiments and structural optimization,a color filter model with high transmittance and saturation in the 454 nm blue light band is achieved.The preparation process of the plasmon color filter model is also discussed.The filter model's unit structure size as small as 300 nm×300 nm provides an effective solution for lightweight and high-saturation color filter design,with potential applications in optical detection and high-resolution color display fields.
surface plasmoncolor filterguided mode resonancehigh saturationfinite element method
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