Compared with traditional color colorants, structural color has the advantages of high resolution and good stability, which can achieve full modulation in the visible light range. Fully dielectric metasurface structures are proposed to replace plasmonic metasurfaces with higher losses. Due to the existence of a high-order dipole resonance mode in the shortwave range, the improvement in color saturation is limited. The researchers propose a feasible scheme to remove the high-order dipole mode to solve this problem.
In a study published in Express Opticsa research group led by Professor Gao Jinsong from the Changchun Institute of Optics, Fine Mechanics and Physics (CIOMP) of the Chinese Academy of Sciences (CAS) has proposed an all-dielectric grating structure color filter with narrow bandwidth and high quality factor.
Using the finite difference time domain method, the researchers conducted an extensive comparative study on HfO2 gratings and SiO2/HfO2 grids. In this process, Gao and his group found that adding SiO2 layer effectively suppressed the generation tendency of high-order dipole mode and improved structural color saturation. The physical mechanism of the result was explained by the magnetic field distribution and electric field vector diagram. They then explored the influence of structural parameters on the spectral curve and the sensitivity of the polarization state.
Based on the results, the all-dielectric network proposed by the researchers ensures that the reflectivity at the maximum position is close to 1 and the transmission at the non-resonant maximum position exceeds 99%. The realization chromaticity coordinates occupied most of the area of the CIE-1931 chromaticity diagram. By adjusting the duty cycle, the researchers obtained the excellent spectral characteristics with the FWHM = 2 nm and the quality factor Q = 424.5.
According to the researchers, this all-dielectric grating has excellent characteristics of high structural color quality, low half-maximum full-width and high quality factor, which is of great significance for the fields of sensing, display imaging and other areas.
The simplified modal method explores large and high-performance networks in greater depth
Yuanhang Zhao et al, all-dielectric multilayer grating visible color filter with narrow band and high quality factor, Express Optics (2022). DOI: 10.1364/OE.453155
Quote: All Dielectric Lattice Structure Color Filter for Sensing and Display Imaging (Jun 14, 2022) Retrieved June 14, 2022 from https://phys.org/news/2022-06-all-dielectric-filter -imaging.html
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