Evaluation of high-precision phase-shifting electron holography by using hologram simulation

摘要

In phase-shifting electron holography, Fresnel diffraction at an electron biprism introduces distortions to the amplitude and phase of the electron waves, which cause phase errors in the reconstructed phase images. To reduce the phase errors, two correction methods have been proposed, termed Fresnel corrections. In order to evaluate the phase-shifting electron holography with Fresnel corrections, we faithfully simulated holograms by considering the influence of Fresnel diffraction, the quantum noise and the electron wave coherency, and then compared the phase images reconstructed from corrected and uncorrected holograms. We found that the phase error due to Fresnel diffraction was reduced to 1/20 by using Fresnel corrections, and that the phase measurement precision reached 2pi/410 rad. We are able to observe the weak electric field due to positive charges corresponding to five electrons. Copyright (C) 2003 John Wiley Sons, Ltd. [References: 17]