Composite Functional Metasurfaces for Multispectral Achromatic Optics

TL;DR

This paper introduces a novel multilayer metasurface design that corrects chromatic aberrations across the visible spectrum, enabling advanced multispectral achromatic optics with multiple functionalities in a compact form.

Contribution

It presents the first triply RGB achromatic metalens using stacked metasurfaces, significantly reducing chromatic aberrations for broadband optical applications.

Findings

Demonstrated a triply RGB achromatic metalens in the visible range

Achieved functional beam shaping for STED microscopy

Created a lens with anomalous dispersive focusing

Abstract

Nanostructured metasurfaces offer unique capabilities for local control of the phase and amplitude of transmitted and reflected optical waves. Based on this potential, a large number of metasurfaces have been proposed in recent years as alternatives to standard optical elements. In most cases, however, these elements suffer from large chromatic aberrations, thus limiting their usefulness for multi-wavelength or broadband applications. Here, in order to alleviate and correct the chromatic aberrations of individual diffractive elements, we introduce dense vertical stacking of independent metasurfaces, where each layer comprises a different material, and is optimally designed for a different band within the visible spectrum. Using this approach, we demonstrate the first triply RGB achromatic metalens in the visible range and perform color imaging with this lens. We further demonstrate functional beam shaping by constructing a self-aligned integrated element for Stimulated Emission Depletion (STED) microscopy and a lens that provides anomalous dispersive focusing. These demonstrations lead the way to the realization of superachromatic ultrathin optical elements and multiple functional operations, all in in a single nanostructured ultrathin element.