SNR calculations (was Re: setup.exe missing from FTP site)

[Warren Young]

Dave Korn wrote:
>   Say, what is the square of a photon, anyway?

One way to square photons is to make them pass through a sufficiently 
small square hole in an opaque plate.  The squared photons will undergo 
a diffraction distortion, so whether the resulting value is 1 or 0 
(photons visible or not) will depend on the angle between the hole and 
your observation apparatus.

The basic technique has already been studied.  You can see a simulation 
of the results here:

	http://en.wikipedia.org/wiki/Image:Square_diffraction.jpg