Here we present the quantum storage of three-dimensional orbital-angular-momentum photonic entanglement in a rare-earth-ion-doped crystal. The properties of the entanglement and the storage process are confirmed by the violation of the Bell-type inequality generalized to three dimensions after storage (S=2.152±0.033). The fidelity of the memory process is 0.993±0.002, as determined through complete quantum process tomography in three dimensions. An assessment of the visibility of the stored weak coherent pulses in higher-dimensional spaces, demonstrates that the memory is highly reliable for 51 spatial modes. These results pave the way towards the construction of high-dimensional and multiplexed quantum repeaters based on solid-state devices. The multimode capacity of rare-earth-based optical processor goes beyond the temporal and the spectral degree of freedom, which might provide a useful tool for photonic information processing.
@article{arxiv.1412.5243,
title = {Quantum Storage of Three-Dimensional Orbital-Angular-Momentum Entanglement in a Crystal},
author = {Zong-Quan Zhou and Yi-Lin Hua and Xiao Liu and Geng Chen and Jin-Shi Xu and Yong-Jian Han and Chuan-Feng Li and Guang-Can Guo},
journal= {arXiv preprint arXiv:1412.5243},
year = {2015}
}