Hello all, I have been searching and trying to find out how entanglement is detected experimentally, but I have a few sticking points. Initially I just want to know the principles behind the experiments. In summary this is how I understand it so far. 1. Entangled photons produced eg in pairs. 2. One member of a pair goes to a detector(A) the second member goes to a different detector(B) 3. Random results detected at A and at B. 4. Results correlate when compared on a photon by photon basis, in other words when members of each separate pair are compared. I think I'm okay with points with points 1,2,and 3. but have been trying to find out how point 4 is achieved experimentally. Am I right in assuming that some sort of coincidence detector is used? Are other methods used? I would also like to see, in more detail, how the experiments are set up. In my searches I have found some nice photographs of the equipment but these have not been helpful. Schematics would be more useful but I haven't found any except for those used to test Bell's theorem. Thank you to anyone who can help.