Re: POLARIZATION

[Leigh Palmer <palmer@sfu.ca>]

> So can one account for the phenomenon (of polarization) in terms of the
> interactions of spinning photons with the polarizer?

If one considers the interaction of a circularly polarized
photon with a (dissipative) linear polarizer, then its
angular momentum is absorbed by the polarizer whether it
is transmitted or not. This would be the case with an
"ideal" Polaroid filter (my dictionary says I must
capitalize that word). I derive this result from the law
of conservation of angular momentum, which, in turn, is
equivalent to the isotropic invariance of physical law.

> I think it is factoidal (i.e. an *apparent* fact), but what annoys me is
> the way the question invites the student to use the "slit" model beyond
> it's useful range, to make a mesh which may or may not catch the
> hypothetical particles of light. The best students will know that they are
> out on a limb. But I suppose this is more than mere regurgitation.

The stupid "slit" model (which I assume is equivalent to the
cake-grid or picket-fence model) is outrageously misleading.
A student should go away "understanding" that the light is
polarized in a plane parallel to the highly conducting grid?
When she actually tries it in the lab with microwaves and a
real cake grid she will find that the plane of polarization
is at right angles to it - or else she won't be able to
understand what is going on at all because of the fixed idea
that the wires must be parallel to the plane of polarization.
I have seen this misconception manifest more than once in a
laboratory situation (and mostly with male students). Score
another triumph for "conceptual" physics over real physics.

Leigh