Design and Optimization of All-Dielectric Metasurfaces for Asymmetric Transmission Properties at Visible Wavelengths

Abstract

This study presents an asymmetric transmission metasurface tailored to effectively block forward-propagating light in the visible spectrum, with a specific focus on the 510nm wavelength, while maximizing transmittance in the backward direction. The optimization of unit cell parameters, including radius, TiO2 and SiO2 thickness, and period, is conducted through Lumerical FDTD simulations. This process enabled precise control over the wavelength range of Fano resonance, resulting in a minimal forward transmittance of 4% for vertically incident light at 510nm wavelength. The refractive index difference between materials further enhanced forward-blocking characteristics through total internal reflection (TIR). Designed for mixed-reality (MR) headsets, the metasurface consistently achieved over 90% average backward transmittance in the visible spectrum, showcasing excellent asymmetric transmission characteristics. Minimizing light leakage in dark environments, this metasurface enhances the stealth capabilities of military MR headsets during nighttime operations.