In article number 1900146, Yang Ming, Yushen Liu, Yan‐qing Lu, and co‐workers investigate parametric down conversion processes in nonlinear metamaterials for generating entangled photon states. As the nanostructures of metamaterials can be flexibly designed, such a system is quite suitable for modulating photonic entanglement in spatial degrees of freedom. The entangled states of orbital angular momentum are considered in detail and proven to be available.

中文翻译：

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光子纠缠：基于非线性超材料的光子纠缠（Laser Photonics Rev. 14（5）/ 2020）

杨明，刘玉深，卢艳卿和他的同事们在编号1900146中研究了非线性超材料中用于产生纠缠光子态的参数下转换过程。由于超材料的纳米结构可以灵活地设计，因此这种系统非常适合在空间自由度上调制光子缠结。轨道角动量的纠缠态被详细考虑并证明是可用的。