Secret sharing is a promising technology for information encryption by splitting the secret information into different shares. However, the traditional scheme suffers from information leakage in decryption process since the amount of available information channels is limited. Herein, we propose and demonstrate an optical secret sharing framework based on the multi-dimensional multiplexing liquid crystal (LC) holograms. The LC holograms are used as spatially separated shares to carry secret images. The polarization of the incident light and the distance between different shares are served as secret keys, which can significantly improve the information security and capacity. Besides, the decryption condition is also restricted by the applied external voltage due to the variant diffraction efficiency, which further increases the information security. In implementation, an artificial neural network (ANN) model is developed to carefully design the phase distribution of each LC hologram. With the advantage of high security, high capacity and simple configuration, our optical secret sharing framework has great potentials in optical encryption and dynamic holographic display.

液晶波前校正器通常基于液晶显示器的工艺制备而成，因此其研制成本高、定制难度大。本文基于掩模光刻法制备液晶波前校正器，以实现液晶波前校正器的专用化、低成本研制。基于掩模光刻技术设计并制备了91像素的无源液晶驱动电极，并封装成液晶光学校正单元。设计并制备了驱动连接电路板，实现了液晶光学驱动单元和驱动电路板的匹配对接。对液晶波前校正器响应特性进行检测。结果显示，其相位调制量为5.5个波长，响应时间为224 ms。利用Zygo干涉仪进行球面波的产生和静态倾斜像差的校正。结果显示，其可以产生正负离焦波前，且对水平倾斜像差校正后，Zernike多项式中第一项的值从1.18降至0.16，校正幅度达86%，实现了像差的有效校正。本文的研究工作可为液晶波前校正器的研制提供新思路，进而拓宽其应用领域和场景。

光子晶体面发射激光器（PCSEL）利用二维光子晶体光栅的布拉格共振实现面发射激光，具有其独特的优势，包括单模性能、在片测试、高功率、低发散角等。相比垂直腔面发射激光器（VCSEL），PCSEL有将近两倍的有源区光限制因子，展现出高速运行的潜力。本文探讨了PCSEL的基本结构和工作原理，并详细分析了影响PCSEL激光器实现高速性能的关键因素。随后，文章系统地介绍了近年来研究者们为实现PCSEL高速性能所做的努力，重点聚焦于通过增强PCSEL的面内限制来缩小激光腔，并提供了相关的研究方向和指导。

荧光转换型近红外发光二极管（NIR pc-LED）具有体积小、谱带宽、峰位易调谐等优点，是新一代NIR光源发展的前沿，其关键在于研发可被蓝光有效激发的高效率宽带近红外荧光粉。LiScSi₂O₆∶Cr³⁺荧光材料的激发波长为460 nm，发射峰位在845 nm，光谱带宽为156 nm，内量子效率为64.4%。基于该体系，本文通过M离子（M = Ga³⁺，Lu³⁺，Y³⁺，Gd³⁺）取代Sc³⁺的方式对其性能进行调控。结果表明，引入M离子易生成杂相或发生相变，降低了材料的发光性能。本文从晶体结构出发对其调控过程进行了分析。

Optical cavities play crucial roles in enhanced light–matter interaction, light control, and optical communications, but their dimensions are limited by the material property and operating wavelength. Ultrathin planar cavities are urgently in demand for large-area and integrated optical devices. However, extremely reducing the planar cavity dimension is a critical challenge, especially at telecommunication wavelengths. Herein, we demonstrate a type of ultrathin cavities based on large-area grown Bi₂Te₃ topological insulator (TI) nanofilms, which present distinct optical resonance in the near-infrared region. The result shows that the Bi₂Te₃ TI material presents ultrahigh refractive indices of >6 at telecommunication wavelengths. The cavity thickness can approach 1/20 of the resonance wavelength, superior to those of planar cavities based on conventional Si and Ge high refractive index materials. Moreover, we observed an analog of the electromagnetically induced transparency (EIT) effect at telecommunication wavelengths by depositing the cavity on a photonic crystal. The EIT-like behavior is derived from the destructive interference coupling between the nanocavity resonance and Tamm plasmons. The spectral response depends on the nanocavity thickness, whose adjustment enables the generation of obvious Fano resonance. The experiments agree well with the simulations. This work will open a new door for ultrathin cavities and applications of TI materials in light control and devices.