Multipartite classically entangled scalar beams

Abstract

Classically entangled light is used to refer to a class of structured beams with space–polarization, polarization–time, and space–time non-separable states akin to entangled states, which enable novel quantum-analog methods and applications in structured light. Here, we argue that classical entanglement is also available for pure scalar beams with multiple non-separable spatial degrees of freedom (DoFs). We theoretically and experimentally demonstrate a class of scalar ray–wave structured light with multiple controllable local DoFs to emulate multipartite entangled states, including the Greenberger–Horne–Zeilinger states. Our work unveils a rich parameter space for high-dimensional and multi-DoF control of structured light to extend applications in classical–quantum regimes.