Generation of ring-shaped optical skyrmion with a high topological number

This is the authors' abstract. We don't add key points for this paper.

Optical skyrmions, unlike their magnetic counterpart, can be generated and detected with a wide variety of topological structures, as they are missing constraints due to energy minimization and available material symmetries. Optical skyrmions are most commonly constructed as superpositions of different propagation-invariant modes in orthogonal polarization states. Experimentally this is problematic, especially for higher-order skyrmions, as large sections of the required polarization structure are imprinted at low light intensity, effectively limiting the range of topological structures to those with low skyrmion numbers. Here, we suggest and demonstrate the generation of optical skyrmions as superpositions of perfect vortex beams, leveraging the inherent consistency of their spatial shape. This allows us to generate beams with ring-shaped and skyrmion numbers up to 20. Furthermore, the spatial dimension of our ring-shaped skyrmions can be easily adjusted, offering potential opportunities for optical communication, precision measurement, and light–matter interaction.