Research On High-performance Plasmonic Color Filters Based On Nanostructure

With the development of micro/nano manufacturing and people’s increasingly high requirements for ultra-high-resolution display and high color saturation printing in life.The filter made of organic dyes or chemical pigments has some defects,such as poor chemical stability,easy to be affected by high temperature,ultraviolet radiation and so on.In recent years,color filters based on surface plasmon can solve these problems well.To this end,this thesis focuses on existing color filter light transmission efficiency not high,low color purity,color gamut area for small and large bandwidth and so on shortcomings.The filter optical and color characteristics are investigated using the finite difference in time domain(FDTD)method with the aim of improving the performance of color filters.The main research works are as follows:(1)In order to ensure that the color filter has excellent filtering performance and achieve the purpose of high efficiency,low broadband and high color saturation plasmonic color filter,this paper designed a high-quality factor plasmonic color filter.Compared with other existing filters,its biggest characteristic is that its reflection,transmission and absorption curves have only one peak value in the visible light range,and almost appear in the same frequency band.The surface plasmon resonance(SPR)occurs when light interacts with the structure,which leads to the induced electric field binding caused by the coupling between the aluminum structure and the electric dipole in the aluminum oxide layer and the uneven distribution of electromagnetic field caused by the obvious enhancement,thus presenting the phenomenon of high transmission and low bandwidth.The results show that different structure parameters can change the transmission spectrum significantly,and the relationship between different structure and quality factor is analyzed,and the structure of color filter with quality factor up to 98 is obtained.(2)In order to solve the problems of low optical transmission efficiency and small color gamut area existing in the filter.In this paper,a novel all-dielectric ring-nanorods color filter is designed to achieve stable and high-resolution display effect.The structure is used to interact with incident light to excite Mie Resonance,which shows strong reflection characteristics in visible light band,so as to achieve different color wide gamut characteristics.The finite difference time domain method was used to compare the reflectance spectra and color display law of nanorods,nanorods and silicon ring-nanorods.At the same time,the influence of the main parameters such as the diameter of nanorods,the diameter of rings,the height and the period on the reflection spectrum and color characteristics was studied.The results show that the reflection characteristics of the designed all-dielectric ring-nanorods filter are greatly improved in a specific optical band.The optimized color filter has a reflectivity of more than 70% in the visible light range,and a wide color gamut can be realized by changing the diameter of nanorods,with a color gamut area of 0.115.(3)In order to solve the problem of low color saturation in plasma color filters,full width at half maxima(FWHM)ultra-narrow reflection type color filter is proposed.The device consists of rectangular silicon nitride nanoblocks of unequal length and width arranged with a period on a silicon dioxide substrate.The effects of parameters such as structural period,length,height of the rectangular blocks,and incident polarization angle on the filter performance are investigated,and a series of tuned spectra with ultra-narrow full width at half maxima in the full visible range can be obtained by proper adjustment.Meanwhile,the reflection efficiency can be maintained up to 0.9 in the full visible range.