(color online) Diagram of the experiment of storage three-dimensional entanglement. The photon pairs were generated in the 20-mm PPKTP crystal via spontaneous parametric down-conversion (SPDC). The photon-pair source was spectrally filtered by the two etalons to match the bandwidth of the memory crystal and separated by the polarized beam splitter (PBS). The signal photons were stored in the Nd³⁺:YVO₄ crystal using the AFC protocol. The OAM state of the signal and idler photons are analyzed by two spatial light modulators (SLMs). The phase-locked mechanical choppers (MCs) were used to protect the single-photon detector (SPD) during the AFC preparation procedure (from Ref. [39]).