My new crystal. All optical calcite’s from china are cheap but they’re yellow as morning glory. That’s why i bought some Icelandic Spar (rhombohedron shape).
Birefringence in an icelandic spar rhombohedron
This is interesting stuff. I demonstrate its features with a standard circular polarizations filter and a red laser.
Polarization: Magic Transparancy
Now this is a pretty nice trick. This is really playing with polarization; youre blocking and twisting and shaping the light. It could be nice if they would have such a thing at kid’s science musea’s, and instead of plastic bags something like magnifying glasses, that would only bend the light so you can only see things through the magnifying glass.