The origin of quantum entanglement experiments based on polarization measurements

Since the 1970s the use of polarization measurements have become standard in optical experiments designed to test the entanglement features of quantum mechanics. Here, we examine the genesis of the conceptual-theoretical and, experimental, configurations that introduced the notion of polarization measurements of quanta traveling in opposite directions. This search uncovers a number of highly relevant publications from the late 1940s that remain largely ignored and unreferenced in today's literature.