Advanced electron holography: a new algorithm for image processing and a standardized quality test for the FEG electron microscope

Off-acis electron holography was used to characterize the structure and morphology of nanometer-sized particles of palladium. The particles were found to be hollow and partially facetted on internal as well as external surfaces. In theoretical developments, the extended Fourier transform (EFT) is discussed and its necessity for true centering of the sideband in electron holography is shown. A reconstruction procedure for off-axis holograms is then proposed using the advantages of the EFT method. Finally, a standard criterion for assessing the effectiveness of a field emission electron microscope for use in electron holography is proposed and illustrated.