Type: 
SSO Seminar
Date-Time: 
Wednesday, October 15, 2014 - 16:00 to 17:00
Location: 
Weniger 304
Event Speaker: 
Professor Ben McMorran, Univ. of Oregon Physics
Local Contact: 
David McIntyre
Abstract: 

Electron vortex beams are composed of helical electron wavefunctions that carry quantized orbital angular momentum (OAM) and an associated magnetic moment. To produce such free electron states, we use nanofabricated diffraction gratings to holographically imprint a phase vortex onto free electron matter waves in a transmission electron microscope (TEM). Electrons in superpositions of orbital states can be used to analyze the dynamic evolution of phase topology in these quantum systems as they propagate through free space and magnetic fields. Additionally, these beams can interact with surfaces and materials in unique ways – OAM-dependent scattering from a specimen in a TEM can provide a “dichroic” signal giving unique information about the electronic states within the material. Recent investigations in plasmonic and magnetic excitations will be highlighted.