autocorrelation function and photon detection

did you try the physics group?

Jamie M wrote: : Does anyone have information on how the second order autocorrelation : function is used to verify that a light source is emitting single : photons?

I suppose you mean: how to verify that the emitted light is in anti-bunched rather than coherent state? In a sense all sources emit single photons.

Regards, Mikko

...which was a bad way to describe things ... of course the coherent state, for instance, is a poissonian superposition of all the photon number eigenstates. I was thinking the bunched / anti-bunched picture, which is dangerous because photons are not tiny balls whizzing through space.

Anyway, isn't the information you're looking for in Wikipedia: tinyurl.com/chxtdzn ?

Regards, Mikko

Remember that light energy and hence intensity is quantized. If your measuring device is sensitive enough you'll be able to detect these low quantized levels at very weak intensities.