This book (Practical Electron Microscopy and Database) is a reference for TEM and SEM students, operators, engineers, technicians, managers, and researchers.

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In the procedure of producing electron holography images, recording interference fringes with an objective wave and a reference wave to form a hologram has a great influence on the spatial resolution of the reconstructed image.

The spatial resolution of electron holography is affected by the resolutions of the electron microscope and of electron interferometry. However, the spatial resolution of the formed images is mostly determined by that of the electron interferometry because the resolution of the electron microscope is higher than that of the electron interferometry. The resolution of the electron interferometry is determined by the interference-fringe spacing of the hologram. In off-axis electron holography, the best resolution, and thus the highest spatial frequency q_max can be reconstructed from the sideband and is given by the spacing s_hol = 1/q_c of the interference fringes, [1] given by,

          --------------------------- [4206]
where,
           k -- The electron wave vector,
           a -- The distance of the back focal plane of the objective lens to the biprism,
           U_F -- The biprism voltage,
           f -- The focal length,
           γ₀U_F -- The deflection angle at the biprism filament.

The biprism voltage U_F is the only variant in Equation 4206. From the resolution point of view, the biprism voltage U_F should be set to as low as possible.

[1] Michael Lehmann, and Hannes Lichte, Tutorial on Off-Axis Electron Holography, Microsc. Microanal. 8, 447–466, 2002.