Counting photons


How do you count a photon - easy - you just count it. But the problem is that in the process of counting it you actually destroy the photon. Scientists have come out with a new way of non-destructively counting photons.
http://www.sciam.com/article.cfm?chanID=sa003&articleID=8F6A0574-E7F2-99DF-3C07BBF73B9A1807&ref=rss