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.

n型AgBiSe₂基化合物的晶格热导率低, 是一种很有潜力的高性能热电材料。然而, 本征AgBiSe₂化合物在300~700 K之间存在两次相变, 使其应用受限。因此, 获得具有稳定结构的AgBiSe₂基化合物, 并优化热电性能至关重要。本研究选择无铅的IV-VI族化合物SnTe与AgBiSe₂进行合金化, 制备了(AgBiSe₂)_1-x(SnTe)_x (x=0.10~0.30)化合物。引入SnTe降低了AgBiSe₂立方相的相变温度, 还有效抑制其发生可逆相变, 得到了稳定的立方相(AgBiSe₂)_0.75(SnTe)_0.25材料。SnTe引起晶格中原子高度无序分布, 导致室温下晶格热导率从0.76 W·m^-1·K^-1(x=0.10)降低到0.51 W·m^-1·K^-1(x=0.30)。进一步Ag位掺杂Nb元素, 可以提升载流子浓度, 增加该体系((Ag_1-yNb_yBiSe₂)_0.75(SnTe)_0.25化合物)的有效质量, 大幅度提升电性能。室温下电导率由77.7 S·cm^-1(基体)增大到158.1 S·cm^-1 (y=0.02)。同时, 材料中的杂质点缺陷也逐步增加, 高温下缺陷散射进一步降低晶格热导率。在700 K时, 晶格热导率由0.56 W·m^-1·K^-1(未掺杂)降低至0.43 W·m^-1·K^-1 (y=0.04), 最终获得了立方相结构稳定的(Ag_0.98Nb_0.02BiSe₂)_0.75(SnTe)_0.25材料, 650 K的ZT达到0.32。上述研究结果表明, (AgBiSe₂)_0.75(SnTe)_0.25化合物是一种具有低晶格热导率和稳定立方相结构的n型热电材料。本研究为高性能相变热电材料的晶体结构调控提出了新解决方案, 有助于进一步推动其应用发展。

Engineering of the orbital angular momentum (OAM) of light due to interaction with photonic lattices reveals rich physics and motivates potential applications. We report the experimental creation of regularly distributed quantized vortex arrays in momentum space by probing the honeycomb and hexagonal photonic lattices with a single focused Gaussian beam. For the honeycomb lattice, the vortices are associated with Dirac points. However, we show that the resulting spatial patterns of vortices are strongly defined by the symmetry of the wave packet evolving in the photonic lattices and not by their topological properties. Our findings reveal the underlying physics by connecting the symmetry and OAM conversion and provide a simple and efficient method to create regularly distributed multiple vortices from unstructured light.