Phase retrieval for Bragg coherent diffraction imaging at high x-ray energies

S. Maddali (1) , Marc Allain (2) , W. Cha (3) , R. Harder (3) , S. Park (3) , P. Kenesei (3) , J. Almer (3) , Y. Nashed (4) , S. Hruszkewycz (1)

1 Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
2 COMiX - Coherent Optical Microscopy and X-rays
3 XSD - X-ray Science Division
4 MCS - Mathematics and Computer Science Division [ANL]

Coherent x-ray beams with energies 50 keV can potentially enable three-dimensional imaging of atomic lattice distortion fields within individual crystallites in bulk polycrystalline materials through Bragg coherent diffraction imaging (BCDI). However, the undersampling of the diffraction signal due to Fourier-space compression at high x-ray energies renders conventional phase-retrieval algorithms unsuitable for three-dimensional reconstruction. To address this problem, we utilize a phase-retrieval method with a Fourier constraint specifically tailored for undersampled diffraction data measured with coarse-pitched detector pixels that bin the underlying signal. With our approach, we show that it is possible to reconstruct three-dimensional strained crystallites from an undersampled Bragg diffraction data set subject to pixel-area integration without having to physically upsample the diffraction signal. Using simulations and experimental results, we demonstrate that explicit modeling of Fourier-space compression during phase retrieval provides a viable means by which to invert high-energy BCDI data, which is otherwise intractable.

Mots clés: Interference & diffraction of light; Molecular & Optical; X-ray beams & optics Atomic

Domaines: Matière Condensée [cond-mat]

S. Maddali, Marc Allain, W. Cha, R. Harder, S. Park, et al.. Phase retrieval for Bragg coherent diffraction imaging at high x-ray energies. Physical Review A : Atomic, molecular, and optical physics [1990-2015], 2019, 99 (5), pp.053838. ⟨10.1103/PhysRevA.99.053838⟩. ⟨hal-02139472⟩