Simulation of in - Line Holograms

Extract

We simulated in-line holograms as obtained from a point projection microscope (PPM) [1]. The principal of the PPM is shown in Fig.1. A coherent electron wave emitted from a point source illuminates a sample transparent to the wave and travels to an electron detector. Since the wave from a point source is divergent the distance d of two points in the object plane results in a magnified distance D in the detector plane. The magnification of this arrangement is given by M=D/d=(z1+z2)/z1, where z1 and z2 are the tip to sample distance and the sample to detector distance, respectively. As no lenses are used we find a highly defocused shadow image in the detector plane. This arrangement is equivalent to Gabor's in-line holography with a physical source in plane of a lens-focused crossover, and the out-of-focus images are in-line electron holograms.