Birefringence

Shows a light ray within a birifringent crystal and reflection and transmission at the surface towards air.
Answers questions like:

* Is the angle of reflection always the same as the angle of incidence?
* What happens in case of perpendicular incidence?
* Are the wavefronts always perpendicular to the direction of the ray?
* How is the polarisation of the rays?
* How is the power distributed between ordinary and extraordinary ray?
* How does the direction of the optic axis influence all of this?