The use of orbital angular momentum (OAM) as an independent dimension for information encryption has garnered considerable attention. However, the multiplexing capacity of OAM is limited, and there is a need for additional dimensions to enhance storage capabilities. We propose and implement orbital angular momentum lattice (OAML) multiplexed holography. The vortex lattice (VL) beam comprises three adjustable parameters: the rotation angle of the VL, the angle between the wave normal and the z axis, which determines the VL’s dimensions, and the topological charge. Both the rotation angle and the VL’s dimensions serve as supplementary encrypted dimensions, contributing azimuthally and radially, respectively. We investigate the mode selectivity of OAML and focus on the aforementioned parameters. Through experimental validation, we demonstrate the practical feasibility of OAML multiplexed holography across multiple dimensions. This groundbreaking development reveals new possibilities for the advancement of practical information encryption systems.

提出了一种基于轨道角动量全息(Orbital Angular Momentum, OAM)和频移的大容量光学信息加密方法。该方法实现了对多个图像信息的并行加密。首先，对多幅原始图像进行采样，采样阵列的采样间隔取决于具有不同拓扑荷数的螺旋相位的空间频率。然后，多个采样图像信息经过随机相位调制、傅里叶变换和频移相位调制后相干叠加构成轨道角动量保留全息图。最后，将不同拓扑荷的螺旋相位分别编码到轨道角动量保留全息图中，得到轨道角动量选择全息图，进行相干叠加后构成最终的单个加密全息图。解密时，轨道角动量复合选择全息图被加载到空间光调制器上，用包含特定拓扑荷数的涡旋光束照射，并经过傅里叶变换获得多个解密信息。该加密系统具有极高的加密灵活性和极大的加密容量，不仅可以在同一拓扑荷下，设计不同的频移因子来并行加密一组多个图像信息，还可以利用不同拓扑荷对多组图像信息进行加密。该方法将涡旋光束的模式设定为一个新的光学密钥，极大地提高了光学加密系统的安全性。此外，该光学加密方法中，待加密图像信息的尺寸不受空间光调制器的像元数量限制，极大地提高了光学实现信息加密的可行性和有效性。仿真实验结果表明该方法具有较高的安全性、抗噪性和抗剪切能力。

图案信息的光学加密在防伪、信息加密存储等方面具有广泛的应用，基于各向异性功能复用的结构色超表面得到发展。基于一维光栅衍射的光学加密超表面由于需要逐个加工掩模或单元结构，从而导致效率低下；传统激光烧蚀波纹结构(LIPSS)效率高，但所形成的结构均匀、一致性差。基于以上难题，提出了一种基于皮秒激光直写相变材料Ge₂Sb₂Te₅得到的改性结构加工光学超表面的方法。首先，表征所制备的GST改性光栅的色散性能，结合改性光栅的偏振依赖性，设计了角度复用的信息加密超表面。实现了在自然光条件下加密，在强光条件下能够选择性解密读取并动态展示的性能。相比于传统加工方法，本方法可在一次直写过程中以同时打印的形式生成一系列光栅结构，提高了加工效率；同时加工得到的光栅结构均匀一致性好，提高了显色效果。利用取向角相差16°的改性光栅实现了无串扰的选择性信息读取，所得结构色均匀鲜艳。本文提出的加工策略在防伪、信息加密存储及可穿戴柔性显示设备等领域有深刻的应用前景。

Optical orbital angular momentum (OAM) multiplexed holography has been implemented as an effective method for information encryption and storage. Multiramp helicoconical-OAM multiplexed holography is proposed and experimentally implemented. The mode selectivity of the multiramp mixed screw-edge dislocations, constant parameter K, and normalized factor are investigated, respectively, which demonstrates that those parameters can be used as additional coding degrees of freedom for holographic multiplexing. The combination of the topological charge and the other three parameters can provide a four-dimensional multiplexed holography and can enhance information capacity.

Luminescent materials often suffer from thermal quenching (TQ), limiting the continuation of their applications under high temperatures up to 473 K. The formation of defect levels could suppress TQ, but rational synthesis and deep understanding of multiple defects-regulated luminescent materials working in such a wide temperature range still remain challenging. Here, we prepare a negative thermal quenching (NTQ) phosphor LiTaO₃ : Tb^{3 +} by introducing gradient defects VTa5-,TbLi2+, and ( V_TaTb_Li)^{3 -} as identified by advanced experimental and theoretical studies. Its photoluminescence significantly becomes intense with rising temperatures and then slowly increases at 373 to 473 K. The mechanism studies reveal that gradient defects with varied trapping depths could act as energy buffer layers to effectively capture the carriers. Under thermal disturbance, the stored carriers could successively migrate to the activators in consecutive and wide temperature zones, compensating for TQ to enhance luminescence emission. This study initiates the synthesis of multi-defect NTQ phosphors for temperature-dependent applications.

超表面是一种厚度在亚波长或波长量级的人工层状材料。可通过调控超表面单元结构上的大小、形状、转角、位移量等自由度，实现对电磁波频率、振幅、相位、偏振等特性的灵活有效调控。超表面具有超薄、宽带、低损耗、易加工、灵活设计，功能强大等特点。文中综述了具有单维度、双维度、多维度光场调控功能的超表面及其在外部激励作用下具有主动可调特性超表面的发展历程，并特别介绍了这些超表面用于信息加密防伪领域的实现方式与优势特点。相比于传统的信息加密防伪技术，超表面信息加密防伪术具有亚波长像素，精密控制，安全系数高等特点，展现了全新视角，拥有广阔的发展前景。