That's a sophisticated project. The quick answer is no, we don't know where to get a great price on these things.
Maybe a little idea connected with the physics might help. The Faraday effect is the rotation of the polarization plane of polarized light caused by a magnetic field in some materials. It's distinct from the optical rotation exhibited by some materials in the absence of a field. The Faraday effect does not reverse sign when the light goes the opposite direction through the material, unlike standard optical rotations. This is ultimately because magnetic fields break time-reversal symmetry.
So of what use is that blather to you? Since the Faraday rotation adds up
as light goes back and forth through a material, you might be able to work with a thin slice of one of your favorite materials (like TGG), put mirrors on it, and have the light make multiple passes back and forth to amplify the effect. (This obviously wouldn't work for non-magnetic rotation.) The light would enter the slab at a slight angle just outside the mirrors, bounce back and forth a few times between the mirrors, then escape on the other side of the mirrors. This mirror geometry geometry would make it hard to use the rotator except on a skinny beam of light, probably obtained from a laser.
The best way to make the mirrors would probably be by depositing metal
films (maybe aluminum) on part of each side of the slab, if you have access to an
evaporator. Otherwise you could just use good mirrors and maybe use a
drop of optical oil between the Faraday slab and the mirrors to reduce
So maybe, if you contact the TGG supplier, explain that you're a high-school student on a very limited budget, describe the project, perhaps they'll give you a break on a few-mm thick slice of TGG or other material.
(published on 12/18/10)