Fully Tunable On-Chip Meta-Generator for Multidimensional Poincar\'e Sphere mapping

TL;DR

This paper introduces a fully tunable on-chip meta-generator that dynamically maps and controls structured light modes across multiple Poincare spheres, enabling compact, precise, and programmable generation of complex light states for advanced optical applications.

Contribution

The work presents the first integrated photonic chip capable of fully tunable, high-dimensional mapping of structured light onto Poincare spheres, combining mode multiplexing and inverse design techniques.

Findings

Supports broadband high-purity OAM mode generation

Enables full-field control of scalar and vectorial states

Achieves dynamic mapping across multiple Poincare spheres

Abstract

The angular momentum of light can be elegantly mapped onto high-order Poincare spheres, providing a powerful framework for describing structured light beams. Such beams have shown extraordinary potential across diverse applications, including high-capacity optical communications, precision metrology, and quantum information processing. While various methods exist for generating structured light beams, the dynamic synthesis and flexible control of arbitrary vectorial states on diverse, multidimensional Poincare spheres still rely on bulky free-space optical components, posing significant challenges for scalability and integration. To date, a fully tunable solution implemented on a single photonic chip has yet to be realized. Here, we present the first fully tunable on-chip meta-generator capable of dynamically mapping arbitrary scalar, vectorial, and hybrid modes onto the full hierarchy of Poincare spheres, and even extending to a high-dimensional Poincare hypersphere within a four-dimensional Hilbert space. Our device is implemented on an eight-channel space-multiplexed multimode silicon photonic integrated circuit, where densely integrated mode multiplexers, amplitude-phase modulators, and an inverse-designed multimode meta-waveguide together enable compact, precise, and programmable control of structured light. The multimode meta-waveguide directly maps eight on-chip guided modes to orbital angular momentum (OAM), supporting broadband generation of high-purity OAM modes with diverse polarization states and topological charges. By simultaneously engineering amplitude, phase, polarization, and topological charge, we achieve full-field control over OAM mode bases, enabling fully tunable access to arbitrary scalar and vectorial states across more than eight distinct Poincare spheres.