MadSci Network: Physics
Query:

Re: Light

Area: Physics
Posted By: Greg Billock, grad student,Caltech
Date: Thu May 1 14:50:49 1997
Area of science: Physics
ID: 861209553.Ph
Message:

Reply:

> Since electro-magnetic radiation (such as visible light) is a magnetic
> field at a 90 degree angle to an electric field, is it possible to
> bend light using other magnetic and/or electric fields?

There are a couple answers to this interesting question, depending on how we look at it. As to "macroscopic" electric and magnetic fields in free space, those won't bend light rays: the fields in a light ray oscillate at hundreds of trillions of times per second, so any effects are cancelled out.

There is, however, and interesting way you can "turn" light with an electric or magnetic field, but you need to have the right kind of material to do it. If you have a Faraday effect material, a magnetic field will rotate (or turn) the polarization of the light going through it. This effect depends on which direction the light is going, and this is how optical isolators are made (which let light pass one direction, but not another). Using high-frequency electric fields and electro-optic crystals, you can create index gratings in the material which can turn a laser beam the "real" way (that is, steer it in another direction).

So, if you are tricky, you can "bend" light using magnetic and electric fields, but it has to be on a "microscopic" level using special materials.

-Greg Billock


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