Re: POLARIZATION

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

Hugh Logan wrote:
> As to why polarizers don't diffract, I am not sure. It might have
> something to do with the fact that not all the parallel strands
> of iodine atoms are in the same plane. It occurred to me that something
> like Bragg scattering might apply, but for d of the order of
> 3 Angstroms and a wavelength lambda of visible light (thousands of
> Angstroms), there would be no possible angle of relection theta in
> 2*d*sin(theta)= n*lambda unless the order n were very high, in which
> the Bragg reflected intensity would be extremely low. This is just a
> guess, but if the light couldn't be Bragg reflected, it might go
> straight through. The periodicity of the iodine strands was studied by
> diffraction of X-rays of much shorter wavelength than visible light.
Correction: If sin(theta) > 1 for n = 1, it would be still greater if 
n were increased. We ran into something like this when we did the 
simulated microwave Bragg diffraction experiment with ball bearings
embedded in styrofoam; I believe n = 3 sometimes
gave a value of sin(theta) > 1. In any case I think the general idea of
my argument holds. It is enough to say that with d = 3 Angstroms
and lambda thousands of Angstroms, and n = 1, that sin(theta) > 1. Thus
no such theta exists.

Hugh Logan