Anti-aliased metasurfaces beyond the Nyquist limit

TL;DR

This paper reveals that the Nyquist sampling criterion is insufficient for metasurface design and introduces anti-aliasing strategies based on lattice diffraction analysis to improve performance across visible to ultraviolet wavelengths.

Contribution

It presents a novel lattice-based diffraction analysis approach and anti-aliasing strategies that surpass the traditional Nyquist criterion for high-performance metasurfaces.

Findings

Nyquist criterion is insufficient for metasurface sampling.

Performance depends on the spectrum and lattice geometry.

Anti-aliasing strategies effectively reduce diffraction artifacts.

Abstract

Sampling is a pivotal element in the design of metasurfaces, enabling a broad spectrum of applications. Despite its flexibility, sampling can result in reduced efficiency and unintended diffractions, which are more pronounced at high numerical aperture or shorter wavelengths, e.g. ultraviolet spectrum. Prevailing metasurface research has often relied on the conventional Nyquist sampling theorem to assess sampling appropriateness, however, our findings reveal that the Nyquist criterion is insufficient for preventing the diffractive distortion. Specifically, we find that the performance of a metasurface is significantly correlated to the geometric relationship between the spectrum morphology and sampling lattice. Based on lattice-based diffraction analysis, we demonstrate several anti-aliasing strategies from visible to ultraviolet regimes. These approaches significantly reduce aliasing phenomena occurring in high numerical aperture metasurfaces.