Adv Mater. 2021 Oct 13:e2105868. doi: 10.1002/adma.202105868. Online ahead of print.
ABSTRACT
Conventional optical diffusers, such as thick volume scatterers (Rayleigh scattering) or microstructured surface scatterers (geometric scattering), lack the potential for on-chip integration and are thus incompatible with next-generation photonic devices. Dielectric Huygens’ metasurfaces, on the other hand, consist of two-dimensional arrangements of resonant dielectric nanoparticles and therefore constitute a promising material platform for ultra-thin and highly efficient photonic devices. When the nanoparticles are arranged in a random but statistically specific fashion, diffusers with exceptional properties are expected to come within reach. In this contribution, we explore how dielectric Huygens’ metasurfaces can be used to implement wavelength-selective diffusers with negligible absorption losses and nearly-Lambertian scattering profiles that are largely independent of the angle and polarization of incident waves. We show that the combination of tailored positional disorder with a carefully-balanced electric and magnetic response of the nanoparticles is an integral requirement for the operation as a diffuser. We experimentally and numerically characterize the directional scattering performance of the proposed metasurfaces and highlight their usability in wavefront-shaping applications. Since our metasurfaces operate on the principles of Mie scattering and are embedded in a glassy environment, they may easily be incorporated in integrated photonic devices, fiber optics, or mechanically robust augmented reality displays. This article is protected by copyright. All rights reserved.
PMID:34652041 | DOI:10.1002/adma.202105868
