Some Analytical Investigations of Phase Contrast Imaging

One of the most popular techniques for converting a spatial phase variation into a spatial intensity variation is the phase contrast imaging scheme originally proposed by F. Zernike 1-3 in 1935. Proceeding mainly from a heuristic point of view, Zernike recognized that, with a conventional imaging system, most of the direct light passes through a small region R in the focal plane while, in many instances, most of the diffracted light is scattered away from this region. If a plate whose transmission function is given by R 1 1943 othenvise (1)