Figure 3: Intensity, polarization and phase of a paraxial versus focused beam.
From: Angular momentum-induced circular dichroism in non-chiral nanostructures
(a) Measurement part of the set-up. A paraxial beam 
is focused by MO
on the sample. Then, MO
collimates the transmitted light and 
is measured with a CCD camera. (b) Intensity and phase plots of the two beams used to carry out the measurement of CDq=1, that is, 
and 
. In the upper row, the intensity and phase of the beams are shown on the back aperture plane of the MO1. Both the intensity and the phase can be described with equation 2. In contrast, the three rows below show the intensity and the phase of the same beams (
and 
) at the focal plane of MO1. As it can be observed, even though their paraxial intensities and phases are analogous, their structure is completely different at the focal plane. This is a direct consequence of the fact that the AM of both beams differ in two units.
