Tunable caustic phenomena in electron wavefields

Amir Hossein Tavabi; Vadim Migunov; Christian Dwyer; Rafal E Dunin-Borkowski; Giulio Pozzi

doi:10.1016/j.ultramic.2015.04.003

Tunable caustic phenomena in electron wavefields

Ultramicroscopy. 2015 Oct:157:57-64. doi: 10.1016/j.ultramic.2015.04.003. Epub 2015 May 22.

Authors

Amir Hossein Tavabi¹, Vadim Migunov², Christian Dwyer², Rafal E Dunin-Borkowski², Giulio Pozzi³

Affiliations

¹ Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C) and Peter Grünberg Institute (PGI), Forschungszentrum Jülich, D-52425 Jülich, Germany. Electronic address: a.tavabi@fz-juelich.de.
² Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C) and Peter Grünberg Institute (PGI), Forschungszentrum Jülich, D-52425 Jülich, Germany.
³ Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C) and Peter Grünberg Institute (PGI), Forschungszentrum Jülich, D-52425 Jülich, Germany; Department of Physics and Astronomy, University of Bologna, Viale B. Pichat 6/2, 40127 Bologna, Italy.

PMID: 26069930
DOI: 10.1016/j.ultramic.2015.04.003

Abstract

Novel caustic phenomena, which contain fold, butterfly and elliptic umbilic catastrophes, are observed in defocused images of two approximately collinear oppositely biased metallic tips in a transmission electron microscope. The observed patterns depend sensitively on defocus, on the applied voltage between the tips and on their separation and lateral offset. Their main features are interpreted on the basis of a projected electrostatic potential model for the electron-optical phase shift.

Keywords: Caustics; Electron optics; Shaped electron beams; Transmission electron microscopy.

Publication types

Research Support, Non-U.S. Gov't