On the design of random metasurface devices

TL;DR

This paper introduces design rules for random metasurfaces with anisotropic elements, analyzing how their density and coupling affect focusing performance, and demonstrates their application in near-infrared metalenses.

Contribution

It proposes a novel approach to designing random metasurfaces, highlighting the influence of density and near-field coupling on their optical performance.

Findings

Performance depends on density for 1D metasurfaces.

2D metasurfaces are affected by density and near-field coupling.

Designs for near-infrared metalenses demonstrate practical application.

Abstract

Metasurfaces are generally designed by placing scatterers in periodic or pseudo-periodic grids. We propose and discuss design rules for functional metasurfaces with randomly placed anisotropic elements. By analyzing the focusing performance of random metasurface lenses as a function of their density and the density of the phase-maps used to design them, we find that the performance of 1D metasurfaces is mostly governed by their density while 2D metasurfaces strongly depend on both the density and the near-field coupling configuration of the surface. The proposed approach is used to design all-polarization random metalenses at near infrared frequencies. Challenges, as well as opportunities of random metasurfaces compared to periodic ones are discussed. Our results pave the way to new approaches in the design of nanophotonic structures and devices from lenses to solar energy concentrators.