Propagation Dynamics of Electron Vortex Pairs

Electron vortex beams carrying orbital angular momentum have been experimentally realized very recently. Here, we present the generation and propagation dynamics of electron vortex pairs embedded in a single beam, using a nanofabricated holographic grating. The rotation of two electron vortices with the same topological charges and the annihilation of two electron vortices with opposite charges were observed. The experimental results are well explained by the Gouy phase shift and confirmed by numerical simulations of the propagation. The results of this study may help develop an intuitive understanding of electron vortex motion and give a new viewpoint for analyzing electron microscope images and phase change in a crystal.