How do scientists/researchers isolate a single photon (for single photon sources)?
How do they know they have isolated it? Is it really totally "isolated"? What is the photon isolated in?
Sorry if this is a basic or general question, just really interested to know what this means, considering that a "vacuum" isn't really empty space.
This is an instructive video on the double slit experiment with photons which is experimenting with single photons. At about 2.5 minutes it explains how the experiment is done with single photons. In a nutshell, by lowering the intensity of a light source to the point of zero emitted by the source and then slowly increasing it.
The detection hinges on the detector of single photons, in this case a photo multiplier. Photo multipliers work by multiplying the input from a single hit into an avalanche that is detectable electronically. For this detector since it has not been isolated from cosmic rays a noise background exists.
If one googles "single photon detectors" a number of commercial detectors come up, using different techniques. One can choose a detector that will fulfill the accuracies necessary in his/her experimental needs.
The double slit experiment supposedly proves a single photon also acts in both wave and particle fashion. A photon is a quanta of photon particles. Sure they will act as a wave and also particles it is made of. The experiment is true only if the slits are small enough to allow a single photon particle or a single photon particle is used to experiment. You cannot make water wave with one water molecule.
