Structural color offers advantages over traditional color dyes. It has high resolution and good stability. This allows for full-tone modulation in visible light. To replace plasmonic metasurfaces that have higher losses, all-dielectric metasurfaces are being considered. The enhancement of color saturation can only be achieved by removing the high-order dipole resonance modes from the short-wave spectrum. To solve the problem, researchers suggest a possible scheme to suppress high-order dipole modes.
A study published in Optics Express by Prof. Gao Jinsong of the Changchun Institute of Optics, Fine Mechanics and Physics of the Chinese Academy of Sciences, (CAS), proposed an all-dielectric grating color filter with narrow bandwidth and high quality factor.
Researchers conducted a detailed comparative study of HfO2 and SiO2/HfO2 gratings using the finite difference method. Gao and his team discovered that adding the SiO2 layer to the gratings effectively suppressed high-order dipole mode generation and increased the structural color saturation. The magnetic field distribution diagram and the electric-field vector diagram explained the physical mechanism. The influence of structural parameters on the spectrum curve and the sensitivity to the polarization state were then investigated.
The researchers' findings show that the all-dielectric dielectric grating they used ensured that the peak position reflectivity is very close to 1 and the non-resonant peak location transmittance exceeds 99 percent. The area covered by the CIE-1931 CIE-1931 chromaticity chart was occupied by the realization chromaticity coordinates. Researchers were able to obtain excellent spectral characteristics by adjusting the duty cycle. The FWHM = 2nm and Q = 424.5 are the best.
According to researchers, this all-dielectric grating has outstanding characteristics such as high structural quality, low full width at half maximum, and high-quality factor. This is important for the fields of display imaging, sensing, and other fields.