Quantitative theory of X-ray interferometers based on dual phase grating: fringe period and visibility

In most of grating x-ray interferometry one needs an absorbing grating as the analyzer to measure high-resolution interference fringes. Dual phase grating interferometry is a technique to get rid of the absorbing grating fur radiation dose reduction. The authors present a quantitative theory of dual grating x-ray interferometry. The theory elucidates the fringe formation mechanism. The derived formulas of fringe period and fringe visibility provide useful tools for design optimization of dual phase grating interferometers. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement