Metalens-array–based high-dimensional and multiphoton quantum source
Lin Li, Zexuan Liu, Xi‐Feng Ren, Shuming Wang, Vin‐Cent Su, Mu Ku Chen, Cheng Hung Chu, Hsin Yu Kuo, Bi‐Heng Liu, Wenbo Zang, Guang‐Can Guo, Lijian Zhang, Zhenlin Wang, Shining Zhu, Din Ping Tsai
Abstract
The development of two-dimensional metasurfaces has shown great potential in quantum-optical technologies because of the excellent flexibility in light-field manipulation. By integrating a metalens array with a nonlinear crystal, we demonstrate a 100-path spontaneous parametric down-conversion photon-pair source in a 10 × 10 array, which shows promise for high-dimensional entanglement and multiphoton-state generation. We demonstrate two-, three- and four-dimensional two-photon path entanglement with different phases encoded by metalenses with fidelities of 98.4, 96.6, and 95.0%, respectively. Furthermore, four-photon and six-photon generation is observed with high indistinguishability of photons generated from different metalenses. Our metalens-array-based quantum photon source is compact, stable, and controllable, indicating a new platform for integrated quantum devices.