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Updated: May 18, 2026

Measurement of X-ray Beam Coherence along Multiple Directions Using 2-D Checkerboard Phase Grating
Published on: October 11, 2016
Coherence length as a figure of merit in multireference near-field acoustical holography
Alan T Wall1, Michael D Gardner, Kent L Gee
1Department of Physics and Astronomy, Brigham Young University, Provo, Utah 84602, USA. alantwall@gmail.com
Abstract:
Multireference partial field decomposition (PFD) can be used to generate coherent holograms for near-field acoustical holography measurements. PFD is most successful when the reference array completely senses all independent subsources, but meeting this requirement is not straightforward when the number of subsources and their locations are ambiguous (such as in aeroacoustic sources). A figure of merit based on spatial coherence lengths, called references per coherence length (RPL(C)), is a useful metric to guide inter-reference spacing in the array design. For numerical, extended, arbitrarily coherent sources one reference per coherence length results in a sufficient reference array.
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