On Tue, 05 Feb 2008 01:20:27 GMT, Gene Fuller
wrote:

Hecht says: "... researchers ... have conducted experiments
in which they literally counted individual photons".

Hecht is quite correct. This is a standard technique in several areas of
physics research. I personally spent several years in my relative youth
designing, building, and using photon counting apparatus.

Hi Gene,

I cannot ascribe its construction to my youth (having built it only 4
or 5 years ago), but I've got one sitting at my elbow that I use as a
random number (AKA white noise) generator. I'm using a Burle (nee
RCA) 931A, which isn't optimal, but still pumps out a flat spectrum to
at least 30MHz. It certainly works fine into my Audio Card.

73's
Richard Clark, KB7QHC