The Design of Highly Reflective All-Dielectric Metasurfaces Based on Diamond Resonators

All-dielectric metasurfaces offer a low-loss alternative to plasmonic metasurfaces. We proposed the configuration for high-reflectivity all-dielectric metasurfaces based on single-crystal diamond (SCD) resonators on fused silica substrate and conducted simulations to optimize and analyze such a configuration via the FDTD solver. We utilized GMR as the design principle to select the configuration and the substrate material, and analyzed the scattering properties of a single SCD resonator by multipole decomposition. Then, we demonstrated that both the cylindrical resonators in square lattice and frustum-shaped resonators in hexagonal lattice can achieve near-unity reflectivity (>99.99%) and ultra-low absorption (<0.001%) at 795 nm, the typical alkali-metal laser wavelength. Additionally, we demonstrated that such a design is quite tolerant of fabrication errors and further supports its potential for realistic applications. To expand the functionality of such devices across multiple wavelengths, dual-band high-reflectivity metasurfaces at 744 nm and 828 nm were also designed. Our work is quite useful for designing diamond-based highly reflective mirrors, paving the way for low-loss all-dielectric reflective metasurfaces in high-power laser applications.