Fig. 4: Ptychographic reconstructions of a monolayer WS₂ sample in different illumination dose conditions.

a–e Reconstructions by mixed-state ptychography using doses 58,000, 3300, 1500, 790, and 375 e Å⁻², respectively. k–o Reconstructions by single-state ptychography. f–j, p–t Corresponding diffractograms of the reconstructions. Scan step size is 0.85 Å for doses from 790 to 58000 e Å⁻². For the dose of 375 e Å⁻², the dataset is selected in an interval of two from the dataset with a dose of 1500 e Å⁻² and the scan step size is 1.69 Å. Three probe modes were used in mixed-state ptychography. The real-space distance of the representative diffraction spots is labeled on i, j and s, t. The non-uniform contrast in the reconstructed images comes from the polymer residual during the sample preparation. Scale bars for real-space images in a–e and k–o are 3 nm, and for diffractograms in f–j and p–t are 0.7 Å⁻¹.