1209.3413 (Giulio Guzzinati et al.)

Observation of the Gouy and Larmor rotations in electron vortex beams    [PDF]

Giulio Guzzinati, Peter Schattschneider, Konstantin Bliokh, Franco Nori, Jo Verbeeck

The Gouy phase anomaly has attracted considerable interest in optics and describes an extra phase shift of a beam going through a focal point compared to a plane wave. Here we directly observe the Gouy phase with electron vortex waves making use of a transmission electron microscope. The image rotation of a superposition of free electron vortex states when focused in a magnetic lens exposes the effect of the Gouy phase in the observed image intensity, dependent on the OAM possessed by the superposition. These observations confirm our previously proposed theoretical predictions on how electron vortex beams behave in a constant magnetic field. Both theory and observations expand the common phenomenon of Larmor rotation in an electron microscope with an OAM dependent Gouy effect.

View original: http://arxiv.org/abs/1209.3413