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Ce contenu n'est pas disponible en français.Broadening the field of view with a fan-shaped source grating
The grating fabrication team recently presented a new solution for the beam alignment of high aspect ratio gratings in imaging systems with an X-ray tube. The field of view of an X-ray Talbot-Lau interferometry setup has been increased by 1.5 times thanks to a source grating with a fan-shaped microstructure. We invented a novel tilted etching method by modulating the electric field during the plasma etching process (see figure below). A model is built with finite elements method and experiments validate the simulation results, showing that a desired tilt profile can be achieved with a proper parameters tuning. The tilted plasma etching method can be applied for many other optics that need a continuous slant gradient.
Schematic diagram of the novel tilted etching method. Local electric field in presence of an electric field modulator (d the inter-slabs distance, h the slab thickness and l the slab width), and a sketched profile of grating lines with tilted etching θ as a function of position x. The equipotential lines are plotted as curved lines in grey scale.