When phyicists say that their laser is firing single photons, how do they know that?

 

How do you verify that it is firing a single photon and not a small cluster of photons?

When phyicists say that their laser is firing single photons, how do they know that?

 

How do you verify that it is firing a single photon and not a small cluster of photons?

 

Attenuate the signal so that the number of transmitted photons is sufficiently small, e.g. if you are emitting 10^10 photon/sec, you attenuate by more than 10 orders of magnitude. You can do single-photon detection to confirm that you have single photons.

You can do single-photon detection to confirm that you have single photons.

How do you do that?

http://en.wikipedia.org/wiki/Single-photon_avalanche_diode is one way

http://en.wikipedia....avalanche_diode is one way

 

 

I take it the amperage/voltage of the cascade current gives a measure of the number of photons that 'hit' it?

I take it the amperage/voltage of the cascade current gives a measure of the number of photons that 'hit' it?

Right.