Research Of Reflection Color Filters Based On Plasmonics

Color filter,as a common optical device,could achieve wavelength selection and display different colors by passing or cutting off the specific wavelength of visible light region.Generally,color filters could be divided into two types:reflective color filters and transmissive color filters.Traditional color filters are mainly made of organic dyes or chemical pigments.However,their resolution cannot be further improved due to the optical diffraction limit,and they have significant problems of instability and performance degradation under high temperature or ultraviolet irradiation.In recent years,plasmonic color filters have attracted widespread attentions because of their high resolution and high stability,which have made them a promising research direction.The reflective color filters as part of them have also attracted great attention from researchers due to its wide application prospects in the fields of applications,such as color printing,anti-counterfeiting,and optical information storage.In this dissertation,a series of researches are carried out about reflective color filters based on plasmonics,and the color filtering performance of reflective color filters are improved and the methods to fabricate them are also expanded.Firstly,we introduce and derive the basic principles of surface plasmon polaritons(SPP),including the Drude model of metals,the dispersion relationship of SPP,characteristic parameters of SPP,different coupling methods to excite SPP and the classification of SPP,which provides a theoretical basis for subsequent researches.In addition;we introduce several common fabrication and characterization methods and techniques of nanostructures,compare their advantages,disadvantages and present their applicable conditions,which laid the experimental foundation for subsequent researches.Secondly,we propose a reflective color filter based on two-dimensional silver nano-cylindrical arrays,which has advantages of high reflectivity,simple nanostructure,wide color filtering range,and polarization independence.The color filter is mainly composed of silver nanodisks on hydrogen silsesquioxane cylinders,and a silver film with nanoholes.The finite-difference time-domain simulation software FDTD Solutions was used to make numerical simulations.The effects of different structural parameters on the filtering effect,and the role of each part of the nanostructures were analyzed.After that,several color filters were experimentally fabricated with selecting appropriate parameters.With the comparative analysis of experimental and simulation results,the feasibility of the color filter and the reliability of the numerical simulation were proved.Then,we propose an angle-independence reflective color filter based on two-dimensional randomly distributed arrays.By eliminating the periodicity of the structure,the color filtering effect is dominated by localized surface plasmon polaritons to achieve the angle insensitivity.The nanocylinder dimer was simulated by FDTD Solutions to analyze the types of surface plasmon polaritons regulated the electromagnetic field under different spacing conditions to determine the design strategy of the randomly distributed array.Utilizing the determined strategy,the reflective color filters are designed,simulated and experimentally fabricated.By easily changing the diameter of the cylinder,the color of the full visible light band is achieved.The simulation of different incident angles verified that the color filter maintains great color stability when the incident angle is even as high as 70°,which proves angle-independence of the color filter.Besides,the Chinese and English logo patterns of Zhejiang University are fabricated by novel reflective color filters,which verifies the actual application performance and prospect.Subsequently,we propose a fabrication method called achromatic Talbot lithography based on synchrotron radiation soft X-ray lithography technology and Talbot effect to achieve fast and large-area fabrication of plasmonic reflective color filters.The synchrotron radiation technology and the synchrotron radiation soft X-ray lithography system are introduced,Talbot effect and achromatic Talbot lithography are also described.The fabrication process of achromatic Talbot grating is discussed and the actual fabrication was carried out.Then,the two-dimensional silver nano-cylinder reflective color filter is fabricated by achromatic Talbot lithography,and the fabrication speed is two orders higher than normal fabrication methods of nanostructures.This fabrication method has various advantages such as high exposure resolution,large exposure area,and high light-source utilization efficiency,which provides the possibility for large-scale mass production of high-resolution plasmonic color filters in the future.Finally,we summarize the research contents and results of this dissertation.In view of some problems in the research and the future development direction of reflective color filters,the outlook is put forward.