Fabrication of two-dimensional hard X-ray diffraction gratings

Hard X-ray grating interferometry has shown promising results in phase and scattering imaging, as well as in metrology applications. Recently, the technique has been extended to two dimensions, recording the full phase gradient vector and a directional scattering signal. Here, we present a process for fabricating the key optical elements required for this technique: phase and absorption gratings with periods of few micrometers and high aspect ratios, with a particular focus on two dimensional grating structures. The fabrication process is based on deep reactive ion etching in silicon and electroplating of gold.