How to read it. Solid rays are the real illumination, traced by the
Ray Optics engine from a point source through the VOA.
The number under each label is the primary beam
radius at that plane.
Teal dashed lines are
sample images, orange dashed lines are
diffraction planes. Both are read off the
post-sample transfer matrix [[A,B],[C,D]]: an image plane is where B = 0 and a diffraction plane is where
A = 0. Neither depends on the condenser, so both stay correct in TEM and STEM alike. The
illumination crossovers listed in the readout are a different thing — images of the
source. With
a focused probe they land on the sample images; with parallel illumination they land on the
diffraction
planes instead, which is why they cannot be used to classify planes. More information in
Help.
Sean Kung ·
sean.kung@ubc.ca ·
bundles Ray Optics Simulation 5.4