Abstract
In the past few years, X-ray phase-contrast and dark-field imaging have evolved to be invaluable tools for non-destructive sample visualisation, delivering information inaccessible by conventional absorption imaging. X-ray phase-sensing techniques are furthermore increasingly used for at-wavelength metrology and optics characterisation. One of the latest additions to the group of differential phase-contrast methods is the X-ray speckle-based technique. It has drawn significant attention due to its simple and flexible experimental arrangement, cost-effectiveness and multimodal character, amongst others. Since its first demonstration at highly brilliant synchrotron sources, the method has seen rapid development, including the translation to polychromatic laboratory sources and extension to higher-energy X-rays. Recently, different advanced acquisition schemes have been proposed to tackle some of the main limitations of previous implementations. Current applications of the speckle-based method range from optics characterisation and wavefront measurement to biomedical imaging and materials science. This review provides an overview of the state of the art of the X-ray speckle-based technique. Its basic principles and different experimental implementations as well as the the latest advances and applications are illustrated. In the end, an outlook for anticipated future developments of this promising technique is given.
Highlights
The first large-scale applications of X-ray imaging can be found in the medical field soon after the discovery of X-rays by Röntgen [1,2]
For the approaches that operate in the sample plane (Depending on the mounting of the diffuser upstream or downstream of the sample, the reconstruction is effectively performed in the sample or the diffuser plane, respectively.), such as 2D X-ray Speckle-Scanning Modes (XSS) and mixed XSS-X-ray Speckle-Vector Tracking (XSVT), it is proportional to the diffuser step size s in the sample plane instead
The latest advances in the operational modes of the technique offer the opportunity to flexibly tune these properties by adjusting reconstruction and scan parameters
Summary
The first large-scale applications of X-ray imaging can be found in the medical field soon after the discovery of X-rays by Röntgen [1,2]. X-ray speckle-based imaging [65], as well as grating interferometry [66] and analyser-based imaging [45], allow one to reconstruct, in addition to the phase-contrast signal, the so-called dark-field image, which is a measure of small-angle scattering from features in the sample that cannot be resolved directly [67,68].The dark-field signal can deliver valuable complementary information about the specimen and has recently been used increasingly for medical applications [69,70,71,72,73,74,75,76,77] and materials science [78,79,80,81,82,83,84] Since it was first proposed a few years ago, X-ray speckle-based phase-contrast and dark-field imaging has drawn significant attention due to its simple, robust and flexible experimental arrangement, cost-effectiveness and relatively low spatial and temporal coherence requirements. Recent applications of the technique are shown, and a summary and outlook for anticipated future developments are given
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
