Electron Vortex Beams with High Quanta of Orbital Angular Momentum
Benjamin James McMorran, Amit K. Agrawal, Ian M. Anderson, Andrew A. Herzing, Henri J. Lezec, Jabez J. McClelland, John Unguris
Analogous to vortices in light optical beams, electron optical beams with helical wavefronts carry orbital angular momentum and promise new capabilities for electron microscopy and other applications. We use nanofabricated diffraction holograms in an electron microscope to produce multiple electron vortex beams with well-defined topological charge. Beams carrying up to 100 quanta, , of orbital angular momentum per electron are observed, demonstrating that a charged massive particle can exhibit stable quantized orbital motion in free space in the absence of any confining potential or external field. Quantized electron vortices open interesting new avenues in physics and provides novel opportunities in electron microscopy and magnetic imaging.