Wave optical theory of in-focus Lorentz microscopy

The purpose of this paper is to evaluate the significance of Foucault-type electron micrographs of thin ferromagnetic films, taking wave optical effects into account. The film is considered as a pure phase object and the diffraction pattern is determined exactly for an extremely collimated incident beam. The illumination on the photographic plate is then evaluated when the diffraction pattern is cut by a knife edge, as a function of the position of the knife edge.