Diffraction at an aperture
(leading to Airy
rings) limits the resolution of many optical systems.
Use
the simulation to show that the size of the central disc
of illumination varies inversely with the size of the aperture
(W).
where
(q is the angular deflection
of the beam at the aperture.)
16% of the intensity (electrons in the TEM) falls outside
the central disc. Adjust the brightness in the simulation
to see how low the intensity of the rings is compared to
that of the central disc. The Rayleigh
criterion for resolution indicates how close together
two points can be brought together before they can no longer
be distinguished as separate.