Optical logic gates play important roles in all-optical logic circuits, which lie at the heart of the next-generation optical computing technology. However, the intrinsic contradiction between compactness and robustness hinders the development in this field. Here, we propose a simple design principle that can possess multiple-input-output states according to the incident circular polarization and direction based on the metasurface doublet, which enables controlled-NOT logic gates in infrared region. Therefore, the directional asymmetric electromagnetic transmission can be achieved. As a proof of concept, a spin-dependent Janus metasurface is designed and experimentally verified that four distinct images corresponding to four input states can be captured in the far-field. In addition, since the design method is derived from geometric optics, it can be easily applied to other spectra. We believe that the proposed metasurface doublet may empower many potential applications in chiral imaging, chiroptical spectroscopy and optical computing.

长期饮用砷污染的水会严重危害人类的健康, 因此亟待开发一种高效且便于分离的除砷吸附剂。本研究采用水热法构建了一种新型高效的除砷吸附材料——埃洛石纳米管负载锆氧化物材料(ZrO₂/HNT)。使用不同手段对制备的复合材料的组成、结构和形貌进行表征, 发现氧化锆纳米颗粒均匀分布在埃洛石纳米管外壁上, 晶型为单斜结构。研究表明, ZrO₂/HNT可快速、有效地去除溶液中的As(V), 吸附反应在30 min内达到平衡。在25 ℃, As(V)的最高吸附容量为27.46 mg/g, 吸附容量随溶液pH升高而降低, 共存离子(除PO₄^3-离子外)对As(V)的吸附性能影响不大。ZrO₂/HNT对As(V)的吸附动力学数据符合准二级动力学模型。吉布斯自由能计算结果和Dubinin-Radushkevich(D-R)等温模型拟合结果表明, As(V)去除过程是吸热、化学吸附反应。傅里叶变换红外光谱(FT-IR)和X射线光电子能谱(XPS)研究表明, As(V)的去除机制主要是As(V)与ZrO₂/HNT吸附材料中ZrO₂表面的羟基发生配体交换, 最终形成稳定的内层配合物。本研究表明合成的ZrO₂/HNT吸附剂可用于去除水溶液中的As(V)。

We report on a power-scalable sub-100-fs laser in the 2-μm spectral range using a Tm³⁺-doped ‘mixed’ (Lu,Sc)₂O₃ sesquioxide ceramic as an active medium. Pulses as short as 58 fs at 2076 nm with an average output power of 114 mW at a pulse repetition rate of approximately 82.9 MHz are generated by employing single-walled carbon nanotubes as a saturable absorber. A higher average power of 350 mW at 2075 nm is obtained at the expense of the pulse duration (65 fs). A maximum average power of 486 mW is achieved for a pulse duration of 98 fs and an optical conversion efficiency of 22.3%, representing the highest value ever reported from sub-100-fs mode-locked Tm lasers.

Structured ultrashort-pulse laser beams, and in particular eigenmodes of the paraxial Helmholtz equation, are currently extensively studied for novel potential applications in various fields, e.g., laser plasma acceleration, attosecond science, and fine micromachining. To extend these prospects further, in the present work we push forward the advancement of such femtosecond structured laser sources into the 2-μm spectral region. Ultrashort-pulse Hermite– and Laguerre–Gaussian laser modes both with a pulse duration around 100 fs are successfully produced from a compact solid-state laser in combination with a simple single-cylindrical-lens converter. The negligible beam astigmatism, the broad optical spectra, and the almost chirp-free pulses emphasize the high reliability of this laser source. This work, as a proof of principle study, paves the way toward few-cycle pulse generation of optical vortices at 2 μm. The presented light source can enable new research in the fields of interaction with organic materials, next generation optical detection, and optical vortex infrared supercontinuum.

The behavior of self-polarization emission in Nd:Y3Al5O12(YAG)/Cr4+:YAG lasers has been proved in some cases. However, the degree and direction of polarization were often sensitive and unstable. We experimentally observed different beam profiles versus the angle of the polarizer relative to the polarization direction of the laser. In order to explore the polarization mechanism, the dynamics of intracavity polarized eigenmodes was analyzed theoretically. Simulative results were well consistent with our experimental observations. It indicated that the linear self-polarization emission was a composite state rather than an intrinsic state. This study contributed to the improvement of the polarization stability in Nd:YAG/Cr4+:YAG passively Q-switched lasers.

为了提高氢化锆表面微弧氧化陶瓷层的致密性及阻氢性能, 采用恒压模式对氢化锆基体进行微弧氧化处理, 在磷酸盐电解液体系下, 研究阶段占空比分别为40%-50%-60%、50%-60%-40%和60%-50%-40%三种情况下陶瓷层的生长过程。利用扫描电子显微镜(SEM)、X射线衍射仪(XRD)、膜层测厚仪分析陶瓷层的形貌、相结构及厚度; 通过真空脱氢实验评价不同阶段占空比模式下获得陶瓷层的阻氢性能。研究结果表明: 不同阶段占空比模式下在ZrH_1.8表面可制得厚度分别为162.6、175.9、158.7 μm的氧化锆陶瓷层, 且所制微弧氧化陶瓷层均由M-ZrO₂、T-ZrO₂以及Zr_0.95Ce_0.05O₂三种物相组成, 阶段占空比对陶瓷层物相组成无显著影响; 阶段占空比为40%-50%-60%条件下, 氢化锆表面所制陶瓷层厚度达到162.6 μm, 氢渗透降低因子(Permeation Reduction Factor, PRF)达到12.5, 阻氢性能较佳。