Re: Polarized light

["Bernard G. Cleyet & Nancy Ann Seese" <georgeann@REDSHIFT.COM>]

Well, also  not quite.

First:  It's the difference between reflection from an insulator and a
conductor, as M. P. explains.  In one case the interaction is with bound
electrons and the other by quasi-free electrons. This difference is
phenomenologically described by a complex index of refraction.

When plane polarized light (not exactly p or s) is reflected by a metal, it
becomes elliptically polarized, because the phase of the components changes
by other than zero or Pi for the s & p components (generally).  Furthermore
as with an insulator, the the reflection coefficients differ.  (excepting
at normal and grazing incidence).

Except for their confusion of the principle angle with the
pseudo-Brewster's angle, Jenknis and White have a good discussion on
metallic reflection.

I'm surprised there is confusion on this matter, as I assume nearly all
optiks texts discuss this, some including derivation of Fresnel's relations
for absorbing media.

bc




Herbert H Gottlieb wrote:

> In response to Scott Krefetz question (below) about
> the lack of polarized light reflections from polished metal,
> Mark Phillips, C.M.Phillips@Metrologic.com replies:
>
> Well, the statement is not EXACTLY true, there is ALWAYS some
> degree of polarization at a reflective interface.
> However, the difference between a transparent material
> (such as glass) and a reflective material (metal) is that the
> component of the polarized light which aligns best with the
> material is TRANSMITTED through the glass, leaving the
> remaining polarization component to be reflected. In a metal,
> with a very high refractive index, it is thought that the
> electron cloud on the surface of the metal responds
> equally well to either polarization component.
>
> Mark Phillips
>
> "Mr. Krefetz" <science98@HOTMAIL.COM> asks
>
> An interesting observation of polarized light. It is polarized when
> reflected off of a transparent material (glass or plastic) which
> follows the explanations from the textbook. But when the
> reflection is from a polished metal surface, the light is not polarized.
>
> Why?
>
> Thanks
> Scott Krefetz
> _________________________________________________________________