[Zurück]

K. Bliokh, I. Ivanov, G. Guzzinati, L. Clark, R. Van Boxem, A. Béché, R. Juchtmans, M. Alonso, P. Schattschneider, F. Nori, J. Verbeeck:
"Theory and applications of free-electron vortex states";
Physics Reports, 690 (2017), S. 1 - 70.

Both classical and quantum waves can form vortices: entities with helical phase fronts
and circulating current densities. These features determine the intrinsic orbital angular
momentum carried by localized vortex states. In the past 25 years, optical vortex beams
have become an inherent part of modern optics, with many remarkable achievements and
applications. In the past decade, it has been realized and demonstrated that such vortex
beams or wavepackets can also appear in free electron waves, in particular, in electron
microscopy. Interest in free-electron vortex states quickly spread over different areas of
physics: from basic aspects of quantum mechanics, via applications for fine probing of
matter (including individual atoms), to high-energy particle collision and radiation processes.
Here we provide a comprehensive review of theoretical and experimental studies
in this emerging field of research. We describe the main properties of electron vortex
states, experimental achievements and possible applications within transmission electron
microscopy, as well as the possible role of vortex electrons in relativistic and high-energy
processes. We aim to provide a balanced description including a pedagogical introduction,
solid theoretical basis, and a wide range of practical details. Special attention is paid
to translating theoretical insights into suggestions for future experiments, in electron
microscopy and beyond, in any situation where free electrons occur.

http://dx.doi.org/10.1016/j.physrep.2017.05.006