Research On Performance Regulation Of Narrowband Filter Based On Metal Subwavelength Optical Structure

Color filter is a common optical element which selectively reflects or transmits a specific wavelength in the visible light band and presents different colors.Its excellent performance makes it widely concerned in liquid crystal display,optical communication,sensing detection and imaging and other fields.Firstly,we introduce the main performances of the metal subwavelength structure narrowband filters.Then,we introduce the specific working principle of different types of metal subwavelength filters.The research progress of surface plasmon filters with metal slits,metal holes,metal-dielectric-metal horizontal cavity and metal-dielectric alternating films metarmaterial as main structures was studied.Metamaterial narrowband color filter has the advantages of compact structure,small size,simple fabrication process and low cost.Finally,a narrowband color filter based on metal-dielectric alternating films metamaterial with adjustable central wavelength is designed,which is based on the structure design and parameter control of the surface plasmon type color filter.Metamaterial narrowband filters have many novel properties,and the narrowband filter performance of the device is simulated by time domain finite difference method and finite element method.In addition,the principle of color filter of the metamaterial narrowband filter is analyzed by the equivalent medium theory.In this paper,the polarization-sensitive narrowband color filter is realized by fabricating periodically arranged metamaterial slit arrays based on alternating metal-dielectric films composed of silver and silicon dioxide.We study the structure and material parameters of the slit width duty ratio(WFF),slit period(P),ratio of thickness of silver film to thickness of dielectric layer(FF),metamaterial thickness(H)and the material of metal films to change the transmittance of the metamaterial filter.We design a narrowband filter with high transmittance and adjustable center wavelength.Finally,the color filter with adjustable center wavelength is realized in the visible light 500 ~ 760 nm band,the full width at half maximum is 17 ~ 30 nm,and the color purity is better;the transmittance is about 50%.At the same time,the fabrication technology of metamaterial narrowband filter is simply introduced.Our work provides a new idea for the design of the new filter.