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Credit: by Y. Shen, E. C. Martínez, C. Rosales-Guzmán
Recent advances in multicomponent condensates, quantum systems, and chiral magnetic materials highlighted nontrivial topological twists and knots in the continuous symmetries of their order parameters, which are known as skyrmions. Skyrmions are originally a special type of particles with topological spin textures, playing important roles in the realms of quantum fields, solid-state physics, magnetic materials, and recently being possible to be controlled in optical fields. Skyrmions have promised critical feature of diversified topology, in other words, skyrmions can have many possible textures, like vortex, hedgehog, saddle, etc., and, be characterized by multiple topological numbers and extendable to unlimited higher dimensions. Despite of the theoretical prediction, the experimental realization of skyrmions with freely tunable topological texture is still elusive.
In their paper recently published on ACS photonics and selected on the journal cover, a joint group of physicists, from the UK, Mexico, and China, report the world-first experimental demonstration of skyrmions with freely tunable topology. Whereby, a generalized family of optical skyrmion, unveiling a new mechanism to transform between various skyrmionic topologies, including prior Néel-, Bloch-, and anti-skyrmion types, via a simple parametric tuning. In addition, a geometric representation is proposed to visualize the complete topological evolution of tunable skyrmions, which can vividly guide topological transformation of skyrmions and the further applications.
As a consequence of this insight, several significant advances and new perspectives are offered, " This is the first know experimental generation of tunable optical skyrmion with controlled transformations among different topological textures, including the anti-skyrmion that was very difficult to generate previously." says Dr. Yijie Shen, the lead author of the paper. “The experimental generation of tunable optical skyrmions is implemented a digital hologram system based on a single spatial light modulator, the results of which show great agreement with our theory, such digital control show great flexibility rather than prior skyrmion generation methods in solid-state physics” says Dr. Carmelo Rosales-Guzmán, the project manager.
Moreover, this model of optical skyrmions can be easily extended to diverse higher-order topological formations. The higher-order skyrmions are still great challenge for both fundamental question and experimental generation in modern physical communities, from high-energy physics to magnetic materials. While, the optical method proposed in this work can really knock this on the head.
Topologically tunable skyrmions enabled by digital structured light modulation can play as effective tools to guide potential applications such as optical communication, information encryption, spin-orbital interaction, and topological phase transition, bring new opportunities in advanced photonics.
Journal
ACS Photonics