Abstract

Electron interferometry is a powerful way to observe the phase variation of a coherent electron beam passed through samples such as quantized magnetic fluxons, and thin crystal films. Until now, the phase variation was measured by optically or digitally reconstructing the Leith-Upatnicks-type electron interferograms recorded in an electron photographic film. We describe an electron phase shifting method to directly measure electron phase variation. A field emission electron gun is used to achieve a coherent electron beam, and a Mollenstetd-Duker type biprism is installed in a 200 kV electron microscope to generate the interference pattern. The phase shift between the two interference electron beams is obtained by slightly varying the angle of the incident beam.

© 1991 Optical Society of America