Generation of tunable optical skyrmions on Skyrme-Poincare sphere

In recent time, the optical-analogous skyrmions, topological quasiparticles with sophisticated vectorial structures, have received an increasing amount of interest. Here we propose theortically and experimentally a generalized family of these, the tunable optical skyrmion, unveiling a new mechanism to transform between various skyrmionic topologies, including Neel-, Bloch-, and antiskyrmion types, via simple parametric tuning. In addition, Poincare-like geometric representation is proposed to visualize the topological evolution of tunable skyrmions, which we termed Skyrme-Poincare sphere, akin to the spin-orbit representation of complex vector modes. To generate experimentally the tunable optical skyrmions we implemented a digital hologram system based on a spatial light modulator, showing great agreement with our theoretical prediction.