Re: POLARIZATION

[Hugh Logan <hlogan@ix.netcom.com>]

Charles Crummer wrote:
> A couple of years back, Ron Tyroler, the demo manager at UC Berkeley,
> showed me a mechanical model of polarization which illustrates circular
> polarization.  It is operated by turning a crank which operates a camshaft
> that moves rods up and down and back and forth.  It was an old apparatus
> and I do not know where it came from.  I haven't found it in current
> manuals.  There are little white balls on the tips of the rods which are
> meant to move the way the electric (or magnetic) field does.

A search of the Internet found an animation (avi) from Brigham Young
University of circularly polarized light both in terms of twisting
2-forms and the more conventional "corkscrew" motion of the electric
vector. This animation is in the context of the application of n-forms
to electromagnetic theory.( http://www.ee.byu.edu/ee/em/circpolr.htm )

There is also a series of lecture demonstrations of elliptical and
circular polararization (mechanical analogies, microwave, and optical)
from the University of Maryland starting at
(http://www.physics.umd.edu/deptinfo/facilities/lecdem/m9-01.htm ).
Just press the "next demo" button to see successive demonstrations.

Hugh Logan