Supertoroidal Skyrmions and Space-Time Superoscillation of Light

Topological complex electromagnetic waves give access to nontrivial light-matter interactions and provide additional degrees of freedom for information transfer. An important example of such electromagnetic excitations are space-time non-separable single-cycle pulses of toroidal topology. Here we introduce an extended family of super-toroidal electromagnetic excitation, which exhibit skyrmionic structure of the electromagnetic fields, multiple singularities, and fractal-like energy backflow. By further introducing bandlimited effect into super-toroidal pulses, we show that space-time non-separable band-limited light fields can exhibit superoscillations simultaneously in the spatial and temporal domains, i.e. can oscillate faster that the highest harmonics of their spectra. The super-toroidal pulses with space-time superoscillation are of interest for transient light-matter interactions, ultrafast optics, spectroscopy, and toroidal electrodynamics.