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 Brewsters's Angle
This special angle of incidence, designated
 occurs when
 .
It follows from Snell's Law and the fact that
that
where shifting the sine by 90 deg makes it a cosine. Dividing both
sides by cos
and again by ni yields
This equation is known as
Brewster's Law, after the man who discovered it empirically.,
Sir David Brewster, the inventor of the kaleidoscope.
Example:
The image of a child reflectsoff a wet city street. At what
angle should the reflection be viewed if it is to be seen
in totally polarized, linear light?
In other words:
Determine the polarization angle at a known interface.
Given:
ni = 1.00 and nt = 1.33
Find:
and so = 53.1 deg.
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