Achieving diffraction-limited resolution in soft-X-ray Fourier-transform holography.

Autor: Geilhufe J; Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, Max-Born-Str. 2A, Berlin 12489, Germany., Pfau B; Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, Max-Born-Str. 2A, Berlin 12489, Germany. Electronic address: bastian.pfau@mbi-berlin.de., Günther CM; Technische Universität Berlin, Institut für Optik und Atomare Physik, Straße des 17. Juni 135, Berlin 10623, Germany; Technische Universität Berlin, Zentraleinrichtung Elektronenmikroskopie (ZELMI), Straße des 17. Juni 135, Berlin 10623, Germany., Schneider M; Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, Max-Born-Str. 2A, Berlin 12489, Germany., Eisebitt S; Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, Max-Born-Str. 2A, Berlin 12489, Germany; Technische Universität Berlin, Institut für Optik und Atomare Physik, Straße des 17. Juni 135, Berlin 10623, Germany.
Jazyk: angličtina
Zdroj: Ultramicroscopy [Ultramicroscopy] 2020 Jul; Vol. 214, pp. 113005. Date of Electronic Publication: 2020 Apr 28.
DOI: 10.1016/j.ultramic.2020.113005
Abstrakt: The spatial resolution of microscopic images acquired via X-ray Fourier-transform holography is limited by the source size of the reference wave and by the numerical aperture of the detector. We analyze the interplay between both influences and show how they are matched in practice. We further identify, how high spatial frequencies translate to imaging artifacts in holographic reconstructions where mainly the reference beam limits the spatial resolution. As a solution, three methods are introduced based on numerical post-processing of the reconstruction. The methods comprise apodization of the hologram, refocusing via wave propagation, and deconvolution using the transfer function of the imaging system. In particular for the latter two, we demonstrate that image details smaller than the source size of the reference beam can be recovered up to the diffraction limit of the hologram. Our findings motivate the intentional application of a large reference-wave source enhancing the image contrast in applications with low photon numbers such as single-shot experiments at free-electron lasers or imaging at laboratory sources.
Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2020 The Authors. Published by Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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