Topological structures of energy flow: Poynting vector skyrmions

TL;DR

This paper uncovers skyrmion-like topological structures formed by Poynting vectors in the focal region of specific light beams, revealing new optical skyrmions with potential implications for light scattering and optical forces.

Contribution

It introduces a new family of optical skyrmions formed by Poynting vectors in free space, demonstrating their transformation and relation to phase singularities.

Findings

Observation of Poynting vector skyrmions in focal regions

Identification of Neel-Bloch-Neel skyrmion transformations

Potential implications for light scattering and optical forces

Abstract

Topological properties of energy flow of light are fundamentally interesting and have rich practical applications in optical manipulations. Here, skyrmion-like structures formed by Poynting vectors are unveiled in the focal region of a pair of counter-propagating cylindrical vector vortex beams in free space. A N\'eel-Bloch-N\'eel skyrmion type transformation of Poynting vectors is observed along the light propagating direction within a volume with subwavelength feature sizes. The corresponding skyrmion type can be determined by the phase singularities of the individual components of the coherently superposed electromagnetic field in the focal region. This work reveals a new family member of optical skyrmions and may introduce novel physical phenomena associated with light scattering and optical force.