Fully diagnosing the spatial properties of X-ray lasers

Based on the moire effect and the Fresnel diffraction theory, a novel techn ique for diagnosing the beam properties is presented and analyzed, which is especially suitable for X-ray lasers. The method makes it possible, in a o ne-shot experimental measurement, to determine the beam quality factor M-2, the effective radius of curvature, the beam width, the far-field divergenc e, and the waist location and radius as well as the spatial coherence and i ts evolution. Numerical simulation proves the validity of the method. Note that the novel moire technique opens an efficient road, for the first time, to fully diagnose the spatial properties of X-ray lasers.