The below is very amateurish, so please correct/modify where needed. Just curious to know the technicalities i.e. how experiments, involving entanglement, are conducted - from a technical perspective For example - Let's take the Bell's tests Entangled pairs would/could be created via SPCD, roughly 1 pair of photons from a trillion of "original" photon hits would emerged entangled. 1. Would trillions of photons be sent through the two channel polarize (with the entangled pairs somehow "marked/known")? 2. or would the entangled ones be somehow filtered and only those sent through the polarisers? 3. for how long currently (state of art) are we able to keep the entanglement? 4. photons move pretty fast, so do we keep bouncing the entangled pairs of mirrors till they enter an experimental apparatus? 5. For all experiments involving entangled particles - do we necessarily, have to, use the coincidence counter to correlate (the entangled photons) - to come up with any meaningful results/conclusions?