Multi-degree-of-freedom hybrid optical skyrmions

Abstract: The optical counterparts of skyrmions have recently been constructed with diverse topological types and by different degrees of freedom, such as field, spins, and Stokes vectors, exhibiting extensive potential in modern information science. However, there is currently no method capable of generating multiple types of optical skyrmions in free space. Here, we present a simple approach for realizing hybrid optical skyrmions of electric field vectors, spin angular momentum and Stokes vectors in a same structured light field. We show that a vector beam truncated by an annular aperture can form an electric field skyrmion in the diffracted light field. In the meantime, electric field meron pairs, spin skyrmions and Stokes skyrmions can be generated by tuning spin-orbital coupling of the incident light.