Research On Sensing Characteristics Of Novel Surface Plasmonic Color Filters

Surface plasmonic color filter based on micro-nano metallic structures have gradually replaced traditional organic dye synthesis process in recent years.It has been used and has a very wide range of applications in display and sensor fields due to its easy modulation and high precision.With the improvement of micro-nano processing technology,surface plasmonic color filter has received more and more attention from researchers.Aiming at the current problems of low surface plasmon resonance intensity of micro-nano metallic structures and narrow filtering range,the research content of this paper mainly includes the design of micro-nano metal structures,modeling and simulation of finite element simulation software,and spectral analysis.The research results are as follows:Firstly,the surface plasmonic color filter structure based on tapered annular aperture arrays was designed.By changing the tilting angle of tapered annular,the shift of the spectrum in the visible and near-infrared range was realized.The effects of the array period,aperture and other parameters on its spectral characteristics as well as the electric field distribution of the planar and transmission resonance modes in the structure were analyzed.The results showed that the array period and aperture have an effect on the reflectance and curve shift of the spectrum,respectively.Then we found the optimal range between the various parameters of the structure.Secondly,the surface plasmonic color filter structure based on Bi-SiO₂-Ag nanorod array was designed.By changing the thickness of the intermediate layer of SiO₂,the filtering effect of the entire visible light region was achieved and the highest reflectivity could reach 96.72%.At the same time,we continue to adjust the thickness of SiO₂ to extend the filter range to the near infrared region.Analyzing the duty cycle and the reflection spectra under TM and TE polarized light,the results showed that high duty cycle can significantly increase the resonance intensity,and the reflection spectra hardly shifted under different polarization spectra,which has polarization insensitive.Compared with other micro-nano metallic structures,these two structures not only extend the filter range to the near-infrared region,but also increase the resonance intensity.The designed Bi-SiO₂-Ag nanorod array structure is much smaller than the F WHM obtained from traditional materials,which-reduces the crosstalk between colors,so the generated colors have higher purity.The two micro-nano metallic structures proposed in this paper have potential applications in fields such as display and sensing.