Publication Type
Journal
Journal Name
Ultramicroscopy
Publication Date
Page Numbers
891 to 898
Volume
110
Issue
7
Abstract
The bright field contrast transfer function is one of the most useful concepts in
conventional transmission electron microscopy. However, the electron Ronchigram
contrast transfer function, as derived by Cowley, is inherently more complicated since it
is not isoplanatic. Here, we derive a local contrast transfer function for small patches in
a Ronchigram and demonstrate its utility for the direct measurement of aberrations from
single Ronchigrams of an amorphous film. We describe the measurement of aberrations
from both simulated and experimental images and elucidate the effects due to higherorder
aberrations, separating those arising from the pre- and post-sample optics, and
partial coherence.
