Photonic spin lattices: symmetry constraints for skyrmion and meron topologies

TL;DR

This paper explores how electromagnetic field symmetry influences the topological spin structures in photonic systems, demonstrating the formation of specific skyrmion and meron lattices through theoretical and experimental methods.

Contribution

It reveals that electromagnetic field symmetry dictates spin topologies in guided modes, introducing a unified framework for understanding electromagnetic field topologies and their transformations.

Findings

Symmetry determines whether hexagonal skyrmion or square meron lattices form.

Experimental demonstration of symmetry-controlled topological spin structures.

Absence of spin-orbit coupling leads to degenerate dynamic field-skyrmions.

Abstract

Symmetry governs many electronic and photonic phenomena in optics and condensed matter physics. Skyrmions and merons are prominent topological structures in magnetic materials, with the topological features determined by the interplay between anisotropy of a material and its magnetization. Here we theoretically show and experimentally demonstrate that the symmetry of the electromagnetic field determines the spin topological properties of the guided modes via spin-orbit coupling and may only result in either hexagonal spin-skyrmion or square spin-meron lattices. We also show that in the absence of spin-orbit coupling these spin topologies are degenerated in dynamic field-skyrmions, unifying description of electromagnetic field topologies. The results provide new understanding of electromagnetic field topology and its transformations as well as new opportunities for applications in quantum optics, spin-optics and topological photonics.