Recent twists in twisted light: A perspective on optical vortices from dielectric metasurfaces

TL;DR

This paper reviews recent advances in using dielectric metasurfaces to generate and control optical vortices, highlighting their significance as topological electromagnetic excitations and their potential applications.

Contribution

It provides a perspective on how metasurfaces have revolutionized the creation and manipulation of optical vortices in the past decade.

Findings

Metasurfaces enable precise control of optical vortex properties.

Optical vortices are now actively engineered using nanostructured metasurfaces.

This technology opens new avenues for topological photonics applications.

Abstract

Optical vortices are the electromagnetic analogue of fluid vortices studied in hydrodynamics. In both cases the traveling wavefront, either made of light or fluid, is twisted like a corkscrew around its propagation axis - an analogy that inspired also the first proposition of the concept of optical vortex. Even though vortices are one of the most fundamental topological excitations in nature, they are rarely found in their electromagnetic form in natural systems, for the exception of energetic sources in astronomy, such as pulsars, quasars and black holes. Mostly optical vortices are artificially created in the laboratory by a rich variety of approaches. Here we provide our perspective on a technology that shook-up optics in the last decade - metasurfaces, planar nanostructured metamaterials - with a specific focus on its use for molding and controlling optical vortices.