Phase determination from a focal series and the corresponding diffraction pattern in electron microscopy for strongly scattering objects

Abstract

The determination of the image forming wavefunction is considered for normal operation of the conventional transmission electron microscope. No assumption is made about the relative strengths of unscattered and scattered radiation. Spatial coherence and monochromaticity are assumed. For objects which are represented by a finite number of Fourier components, an algorithm for phase determination is given. Only the locations and not the intensities of the reflections in the diffraction pattern are needed. The main information used is contained in two or three images with different defocus. Combinations of defocus values which should be avoided since they yield insufficient information, can be determined beforehand from the diffraction pattern.