Re: ATM Re:Moon and Polarizing filters (shortish)

["Clive" <milnecd@wantree.com.au>]

    The figure of 35% or 45% seems to ring a bell, and 9% if two are stacked
90 degrees out of phase......( that is theoretically perfect polarisers )
Interestingly enough..... if you introduce a third one that is phased midway
(45°) between two out of phase polarisers, the actual net light transmission
of the stack increases from 9% to around 20%..!!!!!!!!! ( again from
memory )
.....  I read this in a theoretical physics book , and for those after a
more
complete explanation I would recomend chasing it up....or even testing it
for
yourself...........from memory the text was either in Schrodingers Cat
 Author?)
or one of Hawkins works..... so disbelievers please direct flames to them
not
me..............*S*

-----Original Message-----
From: Jim Cooper <jim@jlcooper.com>
To: atm@shore.net <atm@shore.net>
Date: Saturday, July 11, 1998 3:40 PM
Subject: ATM Re:Moon and Polarizing filters (shortish)


>
>Spencer:
>
>I would seem to me that a "perfect" Polarizing filter would pass quite
>a bit less than 50% of the light. Depending on the "width" of the gaps
>in the "picket fence", it would only pass light exactly in phase, and
>tend to progressively attenuate all other phases until at plus/minus
>90 degrees you'd have complete attenuation.
>
>Anyone have any comment? I looked this up in my old college physics
>text, but it only had equations for the relative magnitude of already
>polarized light passing thru a second filter.  Oh well...
>
>Jim Cooper
>Santa Monica, CA
>