ABERRATION-FREE IMAGE OF AN MGO CRYSTAL EDGE - AN APPLICATION OF IMAGE-RESTORATION IN ELECTRON HOLOGRAPHY

Electron holography has been applied to the observation of the profile image of an MgO (001) surface. The amount of defocus in recording the hologram is estimated by monitoring the standard deviations of the am plitude distribution of restored waves under the assumption that phase objects should show the lowest contrast when the aberration effects a re corrected properly. When the distortion due to the aberration and d efocusing of the electron lenses are removed with inverse filtering in the Fourier space, an aberration-free image of the surface structure is successfully revealed.