Ultrafast Microscopy of Plasmonic Spin Topology 

Abstract: Optics is a natural domain for designing and investigating topological phenomena because it describes the physical structuring and interaction of vectorial electromagnetic fields. My thesis focuses on ultrafast microscopy of plasmonic spin topology on nanometer spatial and femtosecond temporal scales. Topological quasi-particles such as skyrmions and merons, exhibit non-trivial and robust spin topology; hence, they demonstrate potential applications in spin-based electronics, information storage and quantum computing. Furthermore, they illuminate the role of symmetry in defining the structure of the universe and potentially the origin of homochirality of life. By combining ultrafast microscopy, nanofabrication, electromagnetic simulations and mathematical analysis, my research addresses the plasmonic spin topologies, and its role in this rapidly evolving field. Specifically, I theoretically and experimentally demonstrate the structuring of parity-time symmetry conserving magnetoelectric fields in plasmonic vortices with parallel plasmonic electric and magnetic vectorial structures on λ/2 length scales. For this purpose, I introduce nanodevices, which are easily fabricable, for generating unconventional topological plasmonic vortex lattices with defined spin textures.