CD's as parabolic mirrors?

From: John Tinker <jtinker_at_coin.org>
Date: Mon Dec 11 16:14:14 2000

Eric Smith wrote:

> > I believe that the tracks on a CD are concentric rings,
> > which would make a CD something of a reflective Fresnel lens.
> >
>
> It's a single spiral groove, but the macroscopic optical effects are
> probably similar.

But why would it appear concave from the label side, and convex from the
data side?
Received on Mon Dec 11 2000 - 16:14:14 GMT