Re: Total Internal Reflection

[Bob LaMontagne <rlamont@POSTOFFICE.PROVIDENCE.EDU>]

The exposition in Vol II of the Feynman lectures is a wonderful proof
for mechanics problems. It was fun to read that again - thanks to John
for reminding us about it. The original post that started this is total
internal reflection. Again, I would refer people to Feynman's QED for a
rationalization of Fermat's principle in the context of waves. Here he
explains that the minimum path is the one where adjacent paths differ so
little in length that a region of constructive interference of the waves
results. As one moves away from the minimum path the phase relationships
become almost random and there is no consistent interference effect. The
overall effect mimics ray diagrams for reflection and refraction. Of
course, the point of the book is that the same analysis can be done for
QED.

Bob at PC

John Denker wrote:
> Quoting Bernard Cleyet <anngeorg@PACBELL.NET>:
>
> > Is there a simple proof of Fermat's principle?
>
> Feynman, volume II chapter 19.
>
> Probably as simple as it's going to get.
> Recommended.  Really, really, recommended.