Glan-Thompson polarizator

[Niles]

Hi

I understand why a Glan-Thompson polarizator (http://www.thorlabs.de/newgrouppage9.cfm?objectgroup_id=116) works, i.e. birefringence. Currently I am sending light through one, and the beam that goes straight out has a Brewster angle, i.e. it must be polarized parallel to the plane of incidence.

When I turn the polarizator around its axis, then the Brewster angle disappears. I don't understand that, and I can't find the explanation in any of my books on optics. Can anyone help out?

Best,
Niles.

 

[Niles]

I guess its basically a question of what happens when I change the angle between the optic axis and the propagation direction, but how does that change what component comes out where?