Generation of Flying Electromagnetic Donuts

TL;DR

This paper demonstrates the experimental generation of 'Flying Donuts', a novel electromagnetic wave form with a donut-shaped field configuration, using a specially designed metamaterial converter, opening new avenues in telecommunications and sensing.

Contribution

It introduces a method to generate Flying Donuts from conventional pulses with a singular metamaterial converter, a previously theoretical concept now realized experimentally.

Findings

Successfully generated Flying Donuts experimentally

Demonstrated manipulation of electromagnetic fields into donut-like configurations

Potential applications in sensing and telecommunications

Abstract

Transverse electromagnetic plane waves are fundamental solutions of Maxwell's equations. It is less known that a radically different type of solutions has been described theoretically, but has never been realized experimentally, that exist only in the form of short burst of electromagnetic energy propagating in free-space at the speed of light. They are distinguished from transverse waves by a donut-like configuration of electric and magnetic fields with a strong field component along the propagation direction. Here, we report that such 'Flying Donuts' can be generated from conventional pulses using a singular metamaterial converter designed to manipulate both the spatial and spectral structure of the input pulse. The ability to generate Flying Donuts is of fundamental interest, as they shall interact with matter in unique ways, including non-trivial field transformations upon reflection from interfaces and the excitation of toroidal response and anapole modes in matter, thus offering new opportunities for telecommunications, sensing, and spectroscopy.