Re: light slows down in glass

[LUDWIK KOWALSKI <KOWALSKIL@alpha.montclair.edu>]

> Date: Fri, 06 Feb 1998 22:30:16 -0500
> From: Bob Sciamanda <trebor@velocity.net>
> Subject: Re: Light slows down in glass?

> .... Introducing matter into this ALREADY EXISTING field will produce 
> secondary radiation sources out of each mobile charge IMMEDIATELY. 

You are referring to electrons in a dielectric material; nearly all of
them are bound to molecules. They are classical oscillators DRIVEN by
the EM wave. How is n defined in theoretical electromagnetism? Can you 
define it without accepting the fact that the phase velocity is changed 
in the medium? Is this not what we are trying to explain? 

The concept of "DRIVEN mobile charges" does not correspond to the 
"absorption and reemission" model called Huygens principle. Do you
agree that the "naive Huygens principle" can not be used to answer 
the main question of this thread? You are trying to provide an 
alternative model. Am I interpreting you correctly?
                                                     Ludwik Kowalski

> The original field still exists everywhere, and there will be a 
> transient period during which the secondary and original waves 
> superimpose into a steady state wave pattern whose PHASE VELOCITY 
> is c/n (given a transparent material).  The "extinction theorem" of
> Omnes (1915) examined this model in detail (Cf Born & Wolf's Optics book).