6. Fourier analysis of high-resolution scanned images

A high-resolution image is obtained by selecting, with the diaphragm located in the rear focal plane (diffraction plane) of the objective lens and centered on the optical axis of the microscope, a set of diffracted beams around the transmitted beam for a symmetrical Laue orientation. This leads to a reconstruction of the squared modulus of the wave function at the specimen's exit face (a partial reconstruction, as only the Fourier components corresponding to the selected beams are taken into account). Microscope defects (aberrations and focus) modify this image. However, it is easy to simulate, and if we know the experimental conditions well (thickness of the slide, quality of its orientation, microscope characteristics), we can link the image to the distribution of atoms in the structure thanks to simulations (JEMS software). This interferential-type reconstruction leads to a distribution...