Getting more from photons: probing Nature with new forms of light
by
Bo Thidé(Swedish Institute of Space Physics, Uppsala)
→
Europe/Stockholm
Oskar Klein Auditorium
Oskar Klein Auditorium
Description
We have investigated the symmetry properties and the associated
conserved quantities of the electromagnetic field in search for an
optimum set of tools allowing us to extract as much information as
possible from electromagnetic radiation in Nature, notably radio and
radar signals from space. Whereas the well-known EM linear momentum,
associated with translational dynamics and force action, and the spin
part of the angular momentum (SAM, wave polarisation), have been used
in everyday physics and technology for nearly a century, the related
but distinctively different orbital part of the EM angular momentum
(OAM, "twisted photons"), associated with rotational dynamics and
torque action, has only recently been recognised and utilised. Our
work includes, but is not limited to, the electromagnetic orbital
angular momentum (OAM) and other, related topological degrees of
freedom, but aims at investigating all 23 continuous symmetries of the
EM field and suggesting optimised sensor technologies.
Examples of applications of OAM such as spiral imaging of turbulent
space plasma, possible tests of GR by observing Kerr metric-induced OAM
in radiation from nearby rotating black holes, high-contrast
coronagraphy (ten orders of magnitude), and super-resolution that
exceeds the Rayleigh limit by an order of magnitude will be presented.
Outlooks on and applications in wireless communications with high
spectral efficiency will be made. Finally, recent experimental results
on the generation and spiral spectrum analysis of radio beam vorticity
will be presented.
