“…[ 2–5 ] Especially in quantum domain, it is strongly desired to increase the information content encoded on a single photon for higher efficiency, better noise resistance, richer resources, and more flexibility of quantum communications, computations, and simulations. [ 6–9 ] So far, OAM encoded quantum states have been utilized in quantum key distribution, [ 10–13 ] quantum ghost imaging, [ 14,15 ] and high‐dimensional quantum entanglement. [ 16,17 ] The potential application of high‐dimensional quantum information has stimulated the research on generating, [ 18,19 ] manipulating, [ 20,21 ] and detecting [ 22,23 ] the optical quantum states encoded with OAM modes.…”