Valley-locked Optical Spin Skyrmions in Valley Photonic Crystal Waveguides

TL;DR

This paper demonstrates a topologically protected photonic platform enabling robust on-chip directional transport and valley-locked control of optical spin skyrmions, advancing their application in integrated photonic devices.

Contribution

It introduces a novel method to achieve topologically protected, valley-locked optical spin skyrmions for on-chip transport and manipulation in photonic systems.

Findings

Realization of valley-locked spin skyrmions in photonic crystal waveguides.

Robust unidirectional propagation of optical spin skyrmions achieved.

Control over skyrmion polarity via valley degree of freedom.

Abstract

Optical skyrmions have attracted significant attention across diverse physical systems for their promising scenarios in ultra-precise metrology, optical information processing, and quantum technologies. However, the lack of effective method for their on-chip directional transport and manipulation impedes their applications in photonic integrated devices. Here, we demonstrate a photonic platform that utilizes topologically protected valley edge state to achieve robust on-chip directional transport of optical spin skyrmions. These skyrmions originate from spin-orbit coupling within the evanescent field at the valley photonic crystal surface and exist as eigenstates of the topologically protected edge state, ensuring their robust unidirectional propagation. Leveraging the valley degree of freedom of topological edge states, we further achieve valley-locked spin skyrmions, enabling flexible control over the polarity of spin skyrmions. By endowing spin skyrmions with topological protection in momentum space, our work provides an approach for robust on-chip transport and manipulation of spin skyrmions, thereby paving the way for expanding their application potential in photonic systems.