On Wed, 07 May 2003 15:26:48 -0400, Andrew Coppin wrote:

> Here's a simple enough question...
> 
> Is it possible for a transparent substance to be non-reflective? Or are
> all transparent substances inherantly reflective to a certain degree?

	If you work at it hard enough ... If you look at it as an impedance
mismatch causing the reflection then you can layer materials on a surface
which "match" the impedance of air to glass. That gives a number of
smaller reflections which sum to less than the single reflection without
them. That is all the anti-reflection coatings do on lenses. 

	If you could apply a single layer that smoothly transitioned the IOR from
air to glass you would theoretically have no reflection as there would not be a
point of different IORs -- unless a low pressure front moves in or the
humidity changes.

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