Figure 12.
(a) The beam intensity on the detector without any sample in the beam: azimuthal average for the case where the flight tube is flushed with nitrogen (black curve) and the evacuated case (8 × 10−4 mbar, red curve). In this experiment, the coherent nanobeam was created by an FZP. (b) The complex wavefield in the focal plane of the FZP with a central stop, as determined by ptychography. (c) A far-field image of the nanobeam as measured on the pixel detector (cropped to 600 × 600 pixels around the optical axis). [Reprinted with permission from Schroer, Seyrich et al. (2019 ▸), copyright (2019) SPIE.]