Re: Rainbow applet

[Cliff Parker <cparker@EMPOWERING.COM>]

Leigh Palmer wrote:

If you have a laser pointer, try looking at the spot formed by a beam reflected

> from some dielectric surface. Even a vinyl floor or Formica tabletop
> will do; the phenomenon is ubiquitous. Rotate the pointer about its
> axis and you will note a variation in the brightness of the spot. You
> are seeing the effect of the different reflectances of different
> polarizations of the incident beam. Rotate the pointer until the spot
> is at minimum brightness. With this rotational angle held fixed, vary
> the angle of incidence of the beam on the reflecting surface. You
> should be able to find an angle at which the reflected spot has a
> minimum brightness. With the pointer held at this angle, again rotate
> it about its axis and you may be able to get the spot to disappear
> entirely. When you are at this angle (called "Brewster's angle") the
> transmittance of the surface is unity for light polarized in the
> plane of incidence,

Very cool!  It works quite well off of the dingy vinyl floor in my kitchen.  Now
back to my question.  What theory sheds light on why the angle between the plane of
polarization and that of the reflected surface makes a difference in transmittance
and reflection?  I will be following up on the ideas you provided when I get to
school tomorrow.  However, if you have any ideas to throw my way they would be more
than welcome.

Cliff Parker