Complex amplitude control in X-rays for maskless holography*

Phase-contrast imaging provides information about a sample‘s electronic structure, otherwise lost in absorption imaging. Many coherent diffractive X-ray imaging methods offer ways to probe electronic and magnetic ordering by tapping the phase component. Mainly, Fourier transform X-ray holography (FTH) emerged as a tool for single-shot imaging of ultrafast phenomena. FTH relies on the fabrication of a mask directly on the sample, limiting the experimental geometry, the suitable samples, and the region of interest. We describe a way to create a structured illumination to replace the holography mask. It is necessary to control both the amplitude and the wavefield phase using a diffractive optic leading to an immense increase in intensity on the sample, by efficient use of the coherent flux. We will discuss the implementation of the method via quantitative simulations. The technique enables imaging extended samples and broad physical phenomena of great importance, such as magnetism and metal-insulator transitions of quantum solids.