Observation of Toroidal Pulses of Light

TL;DR

This paper reports the first experimental generation and characterization of toroidal light pulses, a novel non-transverse electromagnetic wave type with unique properties, created using nanostructured metasurfaces.

Contribution

It demonstrates the practical realization of toroidal electromagnetic pulses, previously only theoretically predicted, enabling new research avenues in light-matter interactions and quantum information.

Findings

Successful generation of optical and terahertz toroidal light pulses

Characterization of their unique electromagnetic properties

Potential applications in quantum information and fundamental science

Abstract

The transverse electromagnetic waves are major information and energy carriers. In 1996, Hellwarth and Nouchi theoretically identified a radically different, non-transverse type of electromagnetic pulses of toroidal topology. These pulses, which are propagating counterparts of localized toroidal dipole excitations in matter and exhibit unique electromagnetic wave properties, have never been observed before. Here, we report the generation and characterization of such optical and terahertz Toroidal Light Pulses (TLPs), launched from tailored nanostructured metasurfaces comprising toroidal emitters. This achievement paves the way for experimental studies of energy and information transfer with TLPs, their space-time "entanglement", and their light-matter interactions involving anapoles, localized space-time entangled excitations, skyrmions, and toroidal qubits that are of growing interest for the fundamental science of light and applications.