A Study of Electric Charging Using Low-Magnification Electron Holography

As experimentally found by low-magnification holography, both the size of the condenser aperture and the excitation of the objective lens strongly modify the object wavefunction of an electron wave. For example, the phase by electrically charged polystyrene latex spheres attached to a copper grid increases with decreasing excitation of the objective lens and/or decreasing diameter of the condenser aperture. It was also found that a smaller diameter of the condenser aperture increases the phase shift by a carbon foil or magnetic memory cells. In addition, the phase of the image wave is modified by the lateral position of the aperture, whereas different electron densities of the imaging beam have only minor influence on the detected phase shifts.