With the right recoil angle the scattered incident beam is kinematically prohibited, and therefore does not enter the detector.

Angular dependence of the incident beam is controlled by using a tiltable sample stage.

In all of this we have assumed that all wavelengths are present in the incident beam.

At either side the incident beam is reflected to the center of the optical bar by a pentaprism.

Energy in the incident beam is shared between the reflected and refracted waves.

Since the incident beam was assumed to have an intensity of one, this will also give the transmission function:

Resulting from its geometry, the optical switch is sensitive to the angle of the incident beam.

This concerned the way in which electrons were ejected from metals by an incident beam of light.

The direction of the incident beam and the orientation of the object can be varied.

In these cases, topographic imaging is therefore a rather demanding task, unless incident beams with very high intensities are available.