Dresden 2014 – wissenschaftliches Programm

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MI: Fachverband Mikrosonden

MI 6: X-ray Imaging, Holography and Tomography

MI 6.1: Vortrag

Mittwoch, 2. April 2014, 11:00–11:15, MER 02

Phase retrieval in near-field X-ray holography based on separation of object and probe — •Anna-Lena Robisch, Matthias Bartels, and Tim Salditt — Institut für Röntgenphysik, University of Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany

X-ray full-field holography offers quantitative amplitude and phase contrast on the nm-scale. However the image quality suffers form imperfections and aberrations in the illuminating beam.

The general way of reducing such unwanted features is to divide the data by the intensity profile of the illumination before performing phase reconstruction which allows to get the real space image of the sample back. This procedure is mathematically not correct; as the division of the complex illumination in amplitude and phase should be performed in real space where the exit wave right behind the sample can be modeled as the product of the sample's transmission function and the incoming beam. One possibility of reconstructing object and probe in the described way is via ptychography[1].

Here we present an algorithm that can be interpreted as a generalization/extension to ptychography using defocus scanning instead of lateral scanning in one fixed plane. Similar to ptychography simultaneous reconstruction of object and probe is possible [2]. Besides the algorithmic concept and simulations first experimental results using data recorded at the nano-scale imaging beamline DESY/PETRAIII/P10 are shown.

[1] P. Thibault et al., ULTRAMICROSCOPY 109, 338-343 (2009)

[2] A-L. Robisch, T. Salditt, OPT EXPRESS 21(20), (2013)