Magneto-optical Skyrmion for manipulation of arbitrary light polarization

TL;DR

This paper proposes a magneto-optical skyrmion platform that enables full control of light polarization within compact nanophotonic structures, using magnetic fields to manipulate cavity modes and achieve arbitrary polarization states.

Contribution

It introduces a topological skyrmion-based approach for dynamic polarization control in nanophotonics, combining theoretical modeling with numerical simulations to realize tunable polarization states.

Findings

Achieved arbitrary far-field polarization control via magnetic field manipulation.

Demonstrated the formation of a skyrmion with topological charge 2 covering the Poincaré sphere.

Realized tunable bound states in the continuum with specific polarization textures.

Abstract

Dynamic manipulation of arbitrary light polarization is of fundamental importance for versatile optical functionalities, yet realizing such full-Poincar\'e-sphere control within compact nanophotonic architectures remains a formidable challenge. Here, we theoretically propose and numerically demonstrate a magneto-optical skyrmion platform enabling full polarization control of cavity eigenmodes. We reveal the correspondence between the near-field wavefunctions of degenerate dipoles and far-field polarization. By applying multidirectional magnetic fields to magneto-optical photonic crystals, we achieve any complex superposition of orthogonal eigenmodes, thereby realizing arbitrary far-field polarization. This mapping manifests as a skyrmion with a topological charge of 2, guaranteeing coverage of the entire Poincar\'e sphere. Our theoretical model shows excellent agreement with full-wave simulations. Furthermore, we realize bound states in the continuum (BICs) with dynamically tunable polarization textures and demonstrate high-performance polarization-selective emission and transmission. This work establishes a topological paradigm for precise polarization shaping, offering new avenues for advanced optical communication and sensing.