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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The concept of Gabor defocus is applied in electron holography, where both amplitude and phase of the image wave are recorded, in order to minimize crosstalk between the amplitude and phase, and to optimizes the cos(χ) function (for the direct imaging). The Gabor defocus can be given as a function of the Scherzer defocus (Δf_Scherzer) by,

           ----------------------- [2613]
where,
          C_s -- The spherical aberration,
          k -- The electron wave vector.

The Gabor defocus corresponds to the focus of minimum contrast. [1]

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