Open AccessProbing transverse coherence of x-ray beam with 2-D phase grating interferometer
Author(s) -
Shashidhara Marathe,
Xianbo Shi,
Michael Wojcik,
Naresh Kujala,
Ralu Divan,
Derrick C. Mancini,
Albert T. Macrander,
Lahsen Assoufid
Publication year - 2014
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.22.014041
Subject(s) - optics , grating , coherence (philosophical gambling strategy) , physics , interferometry , transverse plane , wavefront , duty cycle , quantum mechanics , engineering , power (physics) , structural engineering
Transverse coherence of the x-ray beam from a bending magnet source was studied along multiple directions using a 2-D π/2 phase grating by measuring interferogram visibilities at different distances behind the grating. These measurements suggest that the preferred measuring orientation of a 2-D checkerboard grating is along the diagonal directions of the square blocks, where the interferograms have higher visibility and are not sensitive to the deviation of the duty cycle of the grating period. These observations are verified by thorough wavefront propagation simulations. The accuracy of the measured coherence values was also validated by the simulation and analytical results obtained from the source parameters. In addition, capability of the technique in probing spatially resolved local transverse coherence is demonstrated.