High-efficiency silicon metasurface mirror on a sapphire substrate

For a possible implementation of high-efficiency Si-nanosphere metasurface mirrors functioning at telecom wavelengths in future gravitational wave detectors, exact dimensional and configuration parameters of the total system, including substrate and protective coating, have to be determined a priori. The reflectivity of such multi-layer metasurfaces with embedded Si nanoparticles and their potential limitations need to be investigated. Here we present the results on how the substrate and protective layer influence optical properties and demonstrate how dimensional and material characteristics of the structure alter light reflectivity. Additionally, we consider the impact of manufacturing imperfections, such as fluctuations of Si nanoparticle sizes and their exact placement, on the metasurface reflectivity. Finally, we demonstrate how high reflectivity of the system can be preserved under variations of the protective layer thickness, incident angle of light, and its polarization.

Automated summary

To implement high-efficiency Si-nanosphere metasurface mirrors in gravitational wave detectors, the exact dimensional and configuration parameters of the total system need to be determined beforehand. The reflective properties and limitations of multi-layer metasurfaces with embedded Si nanoparticles should be investigated. This study demonstrates how the substrate and protective layer influence optical properties, as well as how dimensional and material characteristics affect light reflectivity. Manufacturing imperfections, such as variations in Si nanoparticle sizes and placement, are also considered, along with methods to maintain high reflectivity under different conditions.