Electron holography of long-range electric and magnetic fields

Abstract

The influence of the perturbed reference wave in electron holography is considered for the case of static electromagnetic microfields, whose extension around the observed specimen cannot be neglected. These microfields are called ‘‘long-range’’ to distinguish them from the ‘‘short-range’’ ones, whose extension is strictly limited within the object wave and hence do not perturb the reference wave. Optical reconstructions of experimental holograms of simple electrostatic or magnetic long-range fields have been modeled and simulated. The results indicate that perturbation effects must be taken into account when long-range microfields are investigated by electron holography; it is also shown that their influence can be minimized by increasing the interference distance between the object and reference wave.