Figure 1: Saggital slice through a rat brain. (a-c) reconstruction of the gradient vector field of the refractive index decremment δ. (d,e) reconstruction of δ and improved reconstruction due to the tilted gratings. (Figure from ).1], X-ray grating interferometry has become a popular research subject. Further experiments at our lab sources include the demonstration of grating interferometry based dark-field imaging , as well as developments in biomedical imaging such as the phase-contrast tomography of an infant hand  as well as the clinical evaluation of grating interferometry in mammography applications .
In recent experiments at synchrotron sources, we have shown two ways of recording the full differential phase gradient vector. One approach, using tilted gratings works well in tomography using one-dimensional line grating structures and can lead to improved tomographic reconstructions  as shown for a saggital slice through a rat brain in Figure 1.
The other approach to record the full phase gradient vector is based on two-dimensional grating structures that can be fabricated using deep reactive ion etching. This approach is well suited to radiography and can provide a differential phase signal in two directions, as well as a directional dark-field signal [6,7]. An example of such a directional scattering image of an ant is shown in Figure 2. This method also has interesting applications in in-situ X-ray optics metrology. DOI: 10.1038/nphys265
 F. Pfeiffer, M. Bech, O. Bunk, P. Kraft, E. F. Eikenberry, Ch. Brönnimann, C. Grünzweig, and C. David, Hard X-ray dark-field imaging using a grating interferometer, Nature Materials 7 (2008), 134-137. DOI: 10.1038/nmat2096
 T. Donath, F. Pfeiffer, O. Bunk, C. Grünzweig, E. Hempel, S. Popescu, P. Vock, and C. David, Demonstration of Enhanced Soft-Tissue Contrast in Human Specimen, Investigative Radiology 45 (2010), 445-452. DOI: 10.1097/RLI.0b013e3181e21866
 M. Stampanoni, Z. Wang, T. Thüring, C. David, E. Roessl, M. Trippel, R. A. Kubik-Huch, G. Singer, M. K. Hohl, and N. Hauser, The First Analysis and Clinical Evaluation of Native Breast Tissue Using Differential Phase-Contrast Mammography, Investigative Radiology 46 (2011), 801-806. DOI: 10.1097/RLI.0b013e31822a585f
 S. Rutishauser, T. Donath, C. David, F. Pfeiffer, F. Marone, P. Modregger, and M. Stampanoni, A tilted grating interferometer for full vector field differential x-ray phase contrast tomography, Optics Express 19 (2011), 24890-24896. DOI: 10.1364/OE.19.024890 Open access PDF
 I. Zanette, T. Weitkamp, T. Donath, S. Rutishauser, and C. David, Two-Dimensional X-ray Grating Interferometer, Physical Review Letters 105 (2010), 248102. DOI: 10.1103/PhysRevLett.105.248102
 S. Rutishauser, M. Bednarzik, I. Zanette, T. Weitkamp, M. Börner, J. Mohr, and C. David, Fabrication of two-dimensional hard X-ray diffraction gratings, Microelectronics Engineering 101 (2013), 12-16. DOI: 10.1016/j.mee.2012.08.025