In the UV, CaF2 begins to exhibit small amounts of intrinsic birefringence, which are non-negligible. In Code V there is a very simple way to set up a CaF2 crystal where a crystalline axis is simply established. When a retardance map is calculated for light refracted by such a CaF2 lens, birefringence shows up as “three-point” across the pupil if the light is diverging or converging through a CaF2 crystal with 111 orientation (see https://www.tf.uni-kiel.de/matwis/amat/elmat_en/kap_6/advanced/t6_6_1.html for more details). Or it can show up as a “cross” if the orientation is 001.

First of all, I’m not seeing CaF2 as a Birefringent In/Out material option. I understand I would need to define this in the Birefringent catalog. Second, I need to be able to vary the retardance magnitude and orientation depending on the crystal axis orientation and direction of propagation through the crystal. Any thoughts or suggestions?