  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.
