Large-scale linear operations are the cornerstone for performing complex computational tasks. Using optical computing to perform linear transformations offers potential advantages in terms of speed, parallelism, and scalability. Previously, the design of successive spatially engineered diffractive surfaces forming an optical network was demonstrated to perform statistical inference and compute an arbitrary complex-valued linear transformation using narrowband illumination. We report deep-learning-based design of a massively parallel broadband diffractive neural network for all-optically performing a large group of arbitrarily selected, complex-valued linear transformations between an input and output field of view, each with N_i and N_o pixels, respectively. This broadband diffractive processor is composed of N_w wavelength channels, each of which is uniquely assigned to a distinct target transformation; a large set of arbitrarily selected linear transformations can be individually performed through the same diffractive network at different illumination wavelengths, either simultaneously or sequentially (wavelength scanning). We demonstrate that such a broadband diffractive network, regardless of its material dispersion, can successfully approximate N_w unique complex-valued linear transforms with a negligible error when the number of diffractive neurons (N) in its design is ≥2N_wN_iN_o. We further report that the spectral multiplexing capability can be increased by increasing N; our numerical analyses confirm these conclusions for N_w > 180 and indicate that it can further increase to N_w ∼ 2000, depending on the upper bound of the approximation error. Massively parallel, wavelength-multiplexed diffractive networks will be useful for designing high-throughput intelligent machine-vision systems and hyperspectral processors that can perform statistical inference and analyze objects/scenes with unique spectral properties.

针对不同项目研制过程中碲镉汞线列光导器件在筛选测试和应用中出现的失效模式进行了归纳和总结，并综合碲镉汞材料参数、器件结构尺寸、器件物理、器件制备工艺和器件测试等几个方面因素对器件失效的可能原因进行了分析，首次提出碲镉汞线列光导器件的优值因子作为失效判据，为进一步理解碲镉汞线列光导器件的物理机理以及更好优化器件的筛选过程提供了参考，为碲镉汞线列光导器件应用中出现的失效问题提供了分析和解决的方向。

二氧化硅气凝胶以其低密度、高孔隙率等特性在高温隔热领域显示出广阔的应用前景, 但其脆性和高成本的超临界干燥方式限制了其应用。本研究以乙烯基三甲氧基硅烷(VTMS)和乙烯基甲基二甲氧基硅烷(VMDMS)为前驱体, 通过溶胶凝胶、常压干燥制备了具有高柔性的海绵状有机硅气凝胶, 并研究了前驱体摩尔比对气凝胶微观结构和压缩回弹性能的影响, 以及气凝胶分别在高温有氧和无氧环境中的无机化转变过程。结果表明, 随着前驱体中VTMS/VMDMS比例增加, 气凝胶颗粒变小且堆积更紧密, 其压缩回弹性能也随之降低; 在800 ℃空气氛围中, 气凝胶通过侧基的氧化和主链Si-O-Si的断裂、重排转化为无机SiO₂; 在800 ℃ N₂氛围中, 气凝胶通过裂解反应转化为无机SiO₂和游离碳的混合体, 1000~1400 ℃进一步处理后SiO₂和游离碳经碳热还原反应生成SiO₄、SiCO₃、SiC₂O₂和SiC₃O等无定形的Si-O-C结构和少量β-SiC纳米线; 经1200 ℃碳热还原反应生成的Si-O-C结构具有最优的耐高温氧化性能, 可为制备耐高温氧化Si-O-C气凝胶提供参考。

针对发光二极管（light-emitting diode，LED）光源颜色和光通量精准调控难度高，在生产应用中，调控操作需在电脑等设备上进行的问题，基于格拉斯曼颜色混合定律，结合脉宽调制(pulse width modulation，PWM)调控LED的特性，建立表示PWM与LED照度关系的数学模型，以STM 32微控制器为核心设计了三基色LED调光调色系统。对系统分别进行单色、双色和3色的混光照度实验，数字照度计的测量值与光照数学模型的理论值对比结果表明，该系统在0~370 lx区间内系统的光源照度误差≤4%，合成光色共16 777 216种，且对光源颜色和光通量的调控操作可直接在系统上完成，无需接入其他设备，减少了操作流程，满足工业视觉检测、农作物补光照明和文化旅游对光源颜色和照度的需求。

微腔光频梳在光谱测量、微波光子学、光学原子钟和相干光通信等领域具有重要的应用。宽禁带氮化物半导体材料，如氮化铝（AlN）和氮化镓（GaN）等属于非中心对称晶体，具有二阶和三阶光学非线性系数，宽带的透明窗口以及与蓝宝石衬底较高的折射率差，使其成为研究非线性光子器件的理想平台。文中介绍了氮化物微腔的特性，同时对基于氮化物微腔光梳的相关研究进展，包括AlN微腔中的宽谱光频梳产生和光学参量振荡、GaN微腔中的孤子光频梳产生等进行了介绍和展望。

Active metasurfaces whose optical properties can be tuned by an external stimulus have attracted great research interest recently. Introduction of VO2 phase change material in all-dielectric metasurfaces has been demonstrated to modulate the resonance wavelength and amplitude in the visible to near-infrared wavelength range. In this study, we report a mid-infrared active metasurface based on Si/VO2 hybrid meta-atoms. By incorporating VO2 thin films in different locations of Si/VO2 all-dielectric nanodisks, we demonstrate different modulation amplitude of the electric or magnetic resonance scattering cross sections, leading to drastically different transmission spectrum upon VO2 insulator to metal phase transition. The physical mechanism is originated from the field profiles of the resonance modes, which interact with VO2 differently depending on its locations. Based on this mechanism, we experimentally demonstrated a large modulation of the transmittance from 82% to 28% at the 4.6 μm wavelength. Our work demonstrates a promising potential of VO2-based active all-dielectric metasurface for mid-infrared photonic applications such as infrared camouflage, chemical/biomedical sensing, optical neuromorphic computing, and multispectral imaging.

超宽带单行载流子（UTC）光电探测器因其仅需快速的电子输运过程，较传统PIN探测器具有明显宽带优势，是6G宽带无线通信、太赫兹成像、超宽带噪声发生器等亚太赫兹频段系统中的核心光电子器件之一。面向亚太赫兹频段光电转换需求，针对UTC探测器中大带宽与高饱和功率之间的矛盾问题，分别研究并突破了光生载流子高速输运机理、感性共面波导器件（CPW）结构等关键技术，研制成功带宽106 GHz、饱和输出功率7.3 dBm的双漂移层结构MUTC探测器芯片，和带宽超过150 GHz的超宽带MUTC探测器芯片。