Quantitative x-ray phase-contrast imaging using a single grating of comparable pitch to sample feature size

• Published in: Optics letters Vol. 36; no. 1; p. 55
• Main Authors: Morgan, Kaye S, Paganin, David M, Siu, Karen K W
• Format: Journal Article
• Language: English
• Published: United States 01-01-2011
• Subjects: Image Processing, Computer-Assisted; Optical Devices; X-Rays
• ISSN: 1539-4794
• DOI: 10.1364/OL.36.000055

The ability to quantitatively retrieve transverse phase maps during imaging by using coherent x rays often requires a precise grating or analyzer-crystal-based setup. Imaging of live animals presents further challenges when these methods require multiple exposures for image reconstruction. We present a simple method of single-exposure, single-grating quantitative phase contrast for a regime in which the grating period is much greater than the effective pixel size. A grating is used to create a high-visibility reference pattern incident on the sample, which is distorted according to the complex refractive index and thickness of the sample. The resolution, along a line parallel to the grating, is not restricted by the grating spacing, and the detector resolution becomes the primary determinant of the spatial resolution. We present a method of analysis that maps the displacement of interrogation windows in order to retrieve a quantitative phase map. Application of this analysis to the imaging of known phantoms shows excellent correspondence.