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Inverse-phase composite zone plate providing deeper focus than the normal diffraction-limited depth of X-ray microbeams

A novel type of zone plate (ZP), termed an inverse-phase composite ZP, is proposed to gain a deeper focus than the standard diffraction-limited depth of focus, with little reduction in spatial resolution. The structure is a combination of an inner ZP functioning as a conventional phase ZP and an out...

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Autores principales: Kagoshima, Yasushi, Takayama, Yuki
Formato: Online Artículo Texto
Lenguaje:English
Publicado: International Union of Crystallography 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6337886/
https://www.ncbi.nlm.nih.gov/pubmed/30655468
http://dx.doi.org/10.1107/S1600577518016703
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author Kagoshima, Yasushi
Takayama, Yuki
author_facet Kagoshima, Yasushi
Takayama, Yuki
author_sort Kagoshima, Yasushi
collection PubMed
description A novel type of zone plate (ZP), termed an inverse-phase composite ZP, is proposed to gain a deeper focus than the standard diffraction-limited depth of focus, with little reduction in spatial resolution. The structure is a combination of an inner ZP functioning as a conventional phase ZP and an outer ZP functioning with third-order diffraction with opposite phase to the inner ZP. Two-dimensional complex amplitude distributions neighboring the focal point were calculated using a wave-optical approach of diffraction integration with a monochromatic plane-wave illumination, where one dimension is the radial direction and the other dimension is the optical-axis direction. The depth of focus and the spatial resolution were examined as the main focusing properties. Two characteristic promising cases regarding the depth of focus were found: a pit-intensity focus with the deepest depth of focus, and a flat-intensity focus with deeper depth of focus than usual ZPs. It was found that twice the depth of focus could be expected with little reduction in the spatial resolution for 10 keV X-ray energy, tantalum zone material, 84 nm minimum fabrication zone width, and zone thickness of 2.645 µm. It was also found that the depth of focus and the spatial resolution were almost unchanged in the photon energy range from 8 to 12 keV. The inverse-phase composite ZP has high potential for use in analysis of practical thick samples in X-ray microbeam applications.
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spelling pubmed-63378862019-02-01 Inverse-phase composite zone plate providing deeper focus than the normal diffraction-limited depth of X-ray microbeams Kagoshima, Yasushi Takayama, Yuki J Synchrotron Radiat Research Papers A novel type of zone plate (ZP), termed an inverse-phase composite ZP, is proposed to gain a deeper focus than the standard diffraction-limited depth of focus, with little reduction in spatial resolution. The structure is a combination of an inner ZP functioning as a conventional phase ZP and an outer ZP functioning with third-order diffraction with opposite phase to the inner ZP. Two-dimensional complex amplitude distributions neighboring the focal point were calculated using a wave-optical approach of diffraction integration with a monochromatic plane-wave illumination, where one dimension is the radial direction and the other dimension is the optical-axis direction. The depth of focus and the spatial resolution were examined as the main focusing properties. Two characteristic promising cases regarding the depth of focus were found: a pit-intensity focus with the deepest depth of focus, and a flat-intensity focus with deeper depth of focus than usual ZPs. It was found that twice the depth of focus could be expected with little reduction in the spatial resolution for 10 keV X-ray energy, tantalum zone material, 84 nm minimum fabrication zone width, and zone thickness of 2.645 µm. It was also found that the depth of focus and the spatial resolution were almost unchanged in the photon energy range from 8 to 12 keV. The inverse-phase composite ZP has high potential for use in analysis of practical thick samples in X-ray microbeam applications. International Union of Crystallography 2019-01-01 /pmc/articles/PMC6337886/ /pubmed/30655468 http://dx.doi.org/10.1107/S1600577518016703 Text en © Kagoshima and Takayama 2019 http://creativecommons.org/licenses/by/2.0/uk/ This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.http://creativecommons.org/licenses/by/2.0/uk/
spellingShingle Research Papers
Kagoshima, Yasushi
Takayama, Yuki
Inverse-phase composite zone plate providing deeper focus than the normal diffraction-limited depth of X-ray microbeams
title Inverse-phase composite zone plate providing deeper focus than the normal diffraction-limited depth of X-ray microbeams
title_full Inverse-phase composite zone plate providing deeper focus than the normal diffraction-limited depth of X-ray microbeams
title_fullStr Inverse-phase composite zone plate providing deeper focus than the normal diffraction-limited depth of X-ray microbeams
title_full_unstemmed Inverse-phase composite zone plate providing deeper focus than the normal diffraction-limited depth of X-ray microbeams
title_short Inverse-phase composite zone plate providing deeper focus than the normal diffraction-limited depth of X-ray microbeams
title_sort inverse-phase composite zone plate providing deeper focus than the normal diffraction-limited depth of x-ray microbeams
topic Research Papers
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6337886/
https://www.ncbi.nlm.nih.gov/pubmed/30655468
http://dx.doi.org/10.1107/S1600577518016703
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