Figure 1. Description of setup and sample.

(a) Schematic outline of the experimental setup. Optical axis is not to scale. (b) Scanning electron microscope (SEM) image of a high-resolution test chart made of a 40 by 40 array of starlike structures, patterned into a tungsten layer (thickness 1 μm) on a diamond substrate (thickness 100 μm). Its smallest features have a size of about 50 nm. (c) Single-pulse far-field diffraction pattern recorded as part of the ptychographic dataset (logarithmic scale).