Removing twin images in X-ray fluorescence holography

Abstract

X-ray fluorescence holography is a novel method for three-dimensional (3D) imaging of local atomic structures. However, it suffers from the classical problem of twin images which dates from the original work of D. Gabor. Barton proposed that properly phased combinations of images reconstructed from holograms recorded at several incident energies suppress twin images effects. In this work, the influence of the range and the magnitude of incident energies on reconstructed atomic images is discussed with a single Fe atom and a Fe single crystal used as models for calculations, respectively. Comparing the atomic images reconstructed from these calculated holograms, it is found that the wider is the range of incident energies, the better is the effect of removing twin images. Moreover, with the increase of incident energy, the atomic images are reconstructed with an increasing resolution. At the same time, the difference between their positions and that of the actual atoms decreases. It can be reduced to 10 −2 Å with holograms recorded at high and wide-range incident energies.