Colin Greenshields, Robert Stamps, Sonja Franke-Arnold
Propagating vortex states, which carry orbital angular momentum (OAM), are well known in optics and have recently been demonstrated for electrons. While many analogies exist between photonic and electron vortex states, electron vortices in addition possess an orbital magnetic moment. We show here that propagation of electrons in a superposition of OAM states through a longitudinal magnetic field produces an analogue to optical Faraday rotation. In the optical domain, Faraday rotation is observed for polarisation, but not for superpositions of OAM states. The rotation we predict arises from the additional phase accumulated by the electron as it propagates in the presence of an external magnetic field. We propose an experiment in which this rotation can be measured directly in a transmission electron microscope, and discuss its relation to the well known classical image rotation associated with the Lorentz force.
View original:
http://arxiv.org/abs/1204.4698
No comments:
Post a Comment