Coherent and incoherent effects on the imaging and scattering process in transmission electron microscopy and off-axis electron holography.
The standard treatment for the different plane wave components of incoming electrons in transmission electron microscope imaging is an incoherent superposition. However, projectile electrons in transmission electron microscopes are localized in space, and therefore have to be described as coherent wave-packets. Moreover, recent developments towards ultrafast electron microscopy and dynamic transmission electron microscopy require a description using highly localized wave-packets. Here we will extend the standard stationary modeling of the elastic scattering processes in high-resolution microscopy to a fully time-dependent approach, by using the direct solution of the time-dependent Schrödinger equation. We will draw the connection to the detection of coherent wave-packets, giving explicit implications for the reconstructed waves in off-axis electron holography. Additionally the description of incoherent aberrations is extended to incorporate the influence of the biprism accurately, leading to a modified form of the damping of spatial frequencies.
Koch
Werner
W
Institute for Theoretical Physics, Technische Universität Dresden, 01062 Dresden, Germany. wkoch@theory.phy.tu-dresden.de
Lubk
Axel
A
Grossmann
Frank
F
Lichte
Hannes
H
Schmidt
Ruediger
R