Towards higher-dimensional structured light

TLDR

Structured light involves tailoring optical fields across all degrees of freedom, with orbital angular momentum as a prominent example, but extending control to additional degrees of freedom remains in its infancy. The authors aim to outline methods, challenges, and opportunities for creating, detecting, and controlling multiple degrees of freedom in higher‑dimensional structured light. They propose a roadmap spanning fundamental research to applications, emphasizing larger‑capacity, higher‑security information processing and communication.

Abstract

Structured light refers to the arbitrarily tailoring of optical fields in all their degrees of freedom (DoFs), from spatial to temporal. Although orbital angular momentum (OAM) is perhaps the most topical example, and celebrating 30 years since its connection to the spatial structure of light, control over other DoFs is slowly gaining traction, promising access to higher-dimensional forms of structured light. Nevertheless, harnessing these new DoFs in quantum and classical states remains challenging, with the toolkit still in its infancy. In this perspective, we discuss methods, challenges, and opportunities for the creation, detection, and control of multiple DoFs for higher-dimensional structured light. We present a roadmap for future development trends, from fundamental research to applications, concentrating on the potential for larger-capacity, higher-security information processing and communication, and beyond.