Influence of Angle Range of Recording A Hologram to the Reconstructed Atomic Image in X-ray Fluorescence Holography

Abstract：

X-ray fluorescence holography is a novel method for three-dimensional (3D) imaging of local atomic structure.Theoretically,in an XFH experiment,one has to measure the fluorescence energy on a spherical surface with angular resolution in the degree range to get well-resolved three-dimensional (3D) images of atoms.But in practice,experimental system arrangement of XFH does not allow the measurement of the fluorescent intensity oscillations in the full sphere.The holographic informaion loss because of the limited sampling range (less than 4π) will directly result in defective reconstructed atomic images.In this work,we investigate the influence of angle range and step of recording an X-ray fluorescence hologram on reconstructed atomic images by numerically simulating X-ray fluorescence holograms of Fe single crystal at different recording angle range and step.The Fe atomic images in the plane parallel to the crystal (001) crystallographic plane reconstructed from these simulated holograms can show this influence.The incomplete range of azimuth angle causes inhomogeneous brightness of the reconstructed atomic images.The incomplete range of polar angle causes the reconstructed atomic positions slightly shifted toward the central site and the increase of background brightness.The influence of the polar angle step on the reconstructed atomic images can be ignored if the step is enough small.