Contrast transfer function: Difference between revisions

Revision as of 07:10, 20 October 2021

Revision as of 01:48, 27 July 2023

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The previous description of the contrast transfer function depends on ''linear imaging theory''. Linear imaging theory assumes that the transmitted beam is dominant, there is only weak phase shift by the sample. In many cases, this precondition is not fulilledfulfilled. In order to account for these effects, ''non-linear imaging theory'' is required. With strongly scattering samples, diffracted electrons will not only interfere with the transmitted beam, but will also interfere with each other. This will produce second order diffraction intensities. Non-linear imaging theory is required to model these additional interference effects.<ref>{{Cite journal|title = Contrast Transfer Theory for Non-Linear Imaging|last = Bonevich, Marks|date = May 24, 1988|journal = Ultramicroscopy|doi = 10.1016/0304-3991(88)90230-6|volume=26|issue = 3|pages=313–319}}</ref><ref>This page was prepared in part for Northwestern University class MSE 465, taught by Professor Laurie Marks.</ref>

Contrary to a widespread assumption, the linear/nonlinear imaging theory has nothing to do with [[Diffraction formalism|kinematical diffraction]] or [[Dynamical theory of diffraction|dynamical diffraction]], respectively.