I'd need to verify my sources, but I recall the way photon detection works is by cascade; one photon comes in, and causes a couple of more "things" (I can't rem

I'd need to verify my sources, but I recall the way photon detection works is by cascade; one photon comes in, and causes a couple of more "things" (I can't remember what - electrons, probably) to be dislodged, each of which causes a couple more... and boooom whooooosh very quickly you have something which can be easily noticed by a sensor.