Multiband dielectric metasurface in sandwiched scheme fashioned in the visible range

Abstract A multi-resonance-supported multiband device is proposed. Multi-resonance is typically achieved by combining metal with dielectric nanostructures or by using multiple nanostructures formatting a supercell with optimized geometries (size, period, and/or gap) to support various resonances. In this study, we investigate how higher-order multipoles resonated by sandwich-shaped silicon-rich silicon nitride (SRN) metasurfaces embedded in silica cladding can promote multi-resonance in the visible spectrum, achieving nearly triple peaks at RGB (Red, Green, Blue) wavelengths. Such design enhances the structure integration, while the multi-resonant characteristics enable the metasurface to function as a multiband device with a reduced footprint. Through analytical and numerical analyses, we examine the effects of the metasurface's geometric shape, cladding, and sandwich-shaped nanodisks on resonance, providing design strategies for multi-resonant optical devices forwards multi-spectral imaging, optical sensing, and color displays.