Supertoroidal light pulses as electromagnetic skyrmions propagating in free space

Topology in electromagnetic fields can lead to a range of intriguing and unexpected phenomena. Here the authors describe a family of supertoroidal light pulses that exhibit skyrmionic topological structure flying in free space. Topological complex transient electromagnetic fields 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, the exact solutions of Maxwell's equations described by Hellwarth and Nouchi in 1996 and recently observed experimentally. Here we introduce an extended family of electromagnetic excitation, the supertoroidal electromagnetic pulses, in which the Hellwarth-Nouchi pulse is just the simplest member. The supertoroidal pulses exhibit skyrmionic structure of the electromagnetic fields, multiple singularities in the Poynting vector maps and fractal-like distributions of energy backflow. They are of interest for transient light-matter interactions, ultrafast optics, spectroscopy, and toroidal electrodynamics.

Automated summary

Topology in electromagnetic fields can result in fascinating and unexpected phenomena. The authors introduce a new family of electromagnetic excitation, supertoroidal electromagnetic pulses, with skyrmionic structures and fractal-like energy distributions. These pulses are of interest for transient light-matter interactions, ultrafast optics, spectroscopy, and toroidal electrodynamics.