Figure 1. Experimental setup.

X-rays with E=8.2 keV (selected by a Si-111 monochromator) were focused by a compound refractive lens made of beryllium (Be CRL). To correct for the residual aberrations of the lens, a phase plate was installed immediately following the lens stack. (a) For ptychography the test object—an array of Siemens stars—was placed in the vicinity of the focal plane. The sample was scanned transversely to the beam (x–y raster scan) and far-field diffraction patterns were recorded at each position. (b) Ronchigrams were recorded using a grating test sample with a distinct grating period positioned along the optical axis. Further details can be found in the Methods.