Topological Momentum Skyrmions in Mie Scattering Fields

Abstract: Topological quasiparticles such as skyrmions and merons have recently attracted enormous attentions in the form of diverse optical degrees of freedom. However, these structures have not been explored in the fundamental momentum vectors of optical fields yet. Here, we reveal the universality of forming skyrmion and meron topological textures from the Poynting vector, canonical momentum, and optical spin field, which are generated from multipole Mie scattering fields. Moreover, we analyze the unconditional topological stability of the skyrmionic momentum fields against perturbation and geometric defects. This work reveals the topological properties of multipole scattered field and will spur new phenomena related to optical forces, metamaterial design and unique light-matter interaction.