Hard X‐ray wavefront correction via refractive phase plates made by additive and subtractive fabrication techniques

• Published in: Journal of synchrotron radiation 2020-09, Vol.27 (5), p.1121-1130
• Main Authors: Seiboth, Frank, Brückner, Dennis, Kahnt, Maik, Lyubomirskiy, Mikhail, Wittwer, Felix, Dzhigaev, Dmitry, Ullsperger, Tobias, Nolte, Stefan, Koch, Frieder, David, Christian, Garrevoet, Jan, Falkenberg, Gerald, Schroer, Christian G.
• Format: Article
• Language: English
• Subjects: aberration correction; Beryllium; Diamonds; Geometrical optics; Laser ablation; Lenses; Numerical aperture; phase plate; Phase plates; ptychography; refractive X‐ray optics; Research Papers; Strehl ratio; Wave fronts
• ISSN: 1600-5775; 0909-0495; 1600-5775
• DOI: 10.1107/S1600577520007900

Modern subtractive and additive manufacturing techniques present new avenues for X‐ray optics with complex shapes and patterns. Refractive phase plates acting as glasses for X‐ray optics have been fabricated, and spherical aberration in refractive X‐ray lenses made from beryllium has been successfully corrected. A diamond phase plate made by femtosecond laser ablation was found to improve the Strehl ratio of a lens stack with a numerical aperture (NA) of 0.88 × 10−3 at 8.2 keV from 0.1 to 0.7. A polymer phase plate made by additive printing achieved an increase in the Strehl ratio of a lens stack at 35 keV with NA of 0.18 × 10−3 from 0.15 to 0.89, demonstrating diffraction‐limited nanofocusing at high X‐ray energies. Spherical aberrations in nanofocused X‐ray beams generated by beryllium compound refractive lenses at 8.2 keV and 35 keV are corrected via refractive phase plates fabricated by subtractive and additive technology.