Supertoroidal Electrodynamics

Toroidal electrodynamics is a recently established research area of electromagnetism that involves the study of doughnut-shaped excitations in matter and in free-space. Despite being first considered over 60 years ago, toroidal excitations have been often omitted from the description of matter as they were considered negligible, high order corrections. Owing to the rapid recent advances in metamaterials, toroidal excitations were experimentally observed for the first time in arrays of toroidal metamolecules, providing dominant contributions to the metamaterial response and resulting in counter-intuitive phenomena, such as non-radiating configurations (anapoles) and vector potential sources. More recently, the field of toroidal electrodynamics expanded to include free-space propagating excitations in the form of toroidal light pulses. Such pulses, also known as Flying Doughnuts, are single cycle, space-time non-separable, broadband pulses of toroidal topology. They have been shown to preferentially excite toroidal and anapole resonant modes in nanoparticles and were generated only recently for the first time.