P3D Re: Circular Polarization

[Tom Hubin <thubin@xxxxxxxxx>]

Lawrence A. Haines wrote:

<snip>

> My father-in-law was a friend of Edwin Land.  I clearly remember
> him telling me that Land came to his home one evening in great
> jubilation saying that he had in deed created polarized sheets
> and showed my father-in-law the results of carefully scribing by
> hand on sheets of plastic (I think it was) many very fine and
> close parallel lines.  Then he gleefully showed that by rotating
> the sheets the light was blocked from passing through.  He had
> theorized this result in prior conversations and was delighted to
> find that the theory could be proven.  With this description I
> have seemingly always clearly understood the basic principle of
> poarization which was to force the light waves to pass through in
> only one plane not in all directions.  Or to say it another way,
> to permit only light waves of one plane to pass through.

<snip>

By the way, the light polarization does not pass throught the picket
fence parallel to the pickets as many people would like to believe. The
polarization of the light passing is perpendicular to the pickets.

> I have wondered from time to time if the scribed lines on
> circular polarization (if in fact that is how they are made) are
> concentric or spiral.  Now that I hear about a material lain over
> the basic circular polarized material I am further confused.
> Perhaps this is a subject that is not explainable in simple
> physical terms but I do wonder why not.

Since the light polarization transmitted is perpendicular to the lines,
this would suggest that radial lines, not circular lines, would transmit
circularly polarized light. Now this does not work but the simple model
might lead you to this conclusion.

One of the problems is that the pattern would have to be apparent
anywhere in the medium. Equally spaced parallel lines have no particular
starting point or center. Cut the sheet anywhere and one piece is as
good as another. 

Now make a circular or radial pattern in a sheet of plastic. Cut pieces
from two different parts of the sheet. They do not resemble each other.
So this method cannot be applied on this scale.  

That is not to say that you could not have an array of microscopic
concentric circles or radial lines of some sort. But I have no idea
where this would lead.
 
Tom Hubin
thubin@xxxxxxxxx
AO Systems Design


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