Homogenization of metasurfaces formed by random resonant particles in periodical lattices

TL;DR

This paper introduces an analytical homogenization method for two-dimensional metasurfaces composed of randomly fluctuating particles, enabling better prediction of their electromagnetic properties despite fabrication imperfections.

Contribution

The paper presents a simple analytical homogenization approach for random metasurfaces with electric dipole responses, validated through numerical modeling.

Findings

Fluctuations increase diffuse scattering in metasurfaces.

The method accurately predicts electromagnetic behavior of random arrays.

Applicable to oblique incidence and magnetic dipole resonances.

Abstract

In this paper we suggest a simple analytical method for description of electromagnetic properties of a geometrically regular two-dimensional subwavelength arrays (metasurfaces) formed by particles with randomly fluctuating polarizabilities. Such metasurfaces are of topical importance due to development of mass-scale bottom-up fabrication methods, for which fluctuations of the particles sizes, shapes, and/or composition are inevitable. Understanding and prediction of electromagnetic properties of such random metasurfaces is a challenge. We propose an analytical homogenization method applicable for normal wave incidence on particles arrays with dominating electric dipole responses and validate it with numerical point-dipole modeling using the supercell approach. We demonstrate that fluctuations of particles polarizabilities lead to increased diffuse scattering despite the subwavelength lattice constant of the array. The proposed method can be readily extended to oblique incidence and particles with both electric and magnetic dipole resonances.