Regensburg 2022 – wissenschaftliches Programm

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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 25: Poster

KFM 25.14: Poster

Donnerstag, 8. September 2022, 15:00–18:00, P2

X-ray off-axis holography using iterative phase retrieval and waveguide beam splitters — •Paul Meyer and Tim Salditt — Institute for X-ray Physics, Georg August University of Göttingen, Germany

Propagation based phase contrast imaging (PB-PCI) with hard X-rays has become a powerful technique to study weakly absorbing specimen. Iterative algorithms can for example make single cells in a hydrated environment visible by retrieving the phase shift induced by the sample [1].

As image contrast in PB-PCI data arises from phase curvature, the reconstruction of low-frequency signals is challenging. In practice, it often requires support constraints on the sample. This problem does not arise with off-axis holography. Here, information of the phase image is extracted through interference with an additional reference beam that can for example be generated by a beamsplitting waveguide [2].

We observed that introducing such a reference beam in simulations for PB-PCI accelerates convergence and improves accuracy of the iterative phase retrieval (RAAR). We aim to transfer the observed advantage to the practical application of off-axis holography at synchrotron imaging facilities.

[1] Krenkel et al. Three-dimensional single-cell imaging with X-ray waveguides in the holographic regime. Acta Cryst A 73, 282-292 (2017). [2] Fuhse et al. Waveguide-Based Off-Axis Holography with Hard X Rays. Phys. Rev. Lett. 97, 254801 (2006).