[ARC5] WHINK and crystals - plate glass.

[Kenneth G. Gordon]

On 28 Jun 2013 at 9:19, J. Forster wrote:

> Optical flats, used w/ LASERs are probably a whole lot flatter. They
> are often good to 1/100th of a wavelength of roughly 500 nM light, or
> 5 nM.
> 
> They are pretty expensive though. Think $300 for a 1" OD, 1" thick
> one.
> 
> You can sometimes be picked up cheap on eBay.

One thing that has always confused me, and which has held me back from 
attempting to grind crystals to frequency on a piece of "plate glass" is that it 
would seem to me that the glass would not remain "perfectly flat" for very 
long, since the same grinding compound that works on the crystals would 
most certainly also work on the glass at the same time and to the same 
extent.

Might anyone here have any comments to add or corrections to my way of 
thinking about this? Please?

Ken Gordon W7EKB