剪切散斑干涉是一种非接触式、全场高精度光学变形测量技术，由于环境等因素导致采集的散斑条纹图像存在大量随机噪声,进而影响测量精度。传统去噪方法在滤除噪声的同时，容易导致条纹边缘信息的丢失甚至破坏。针对该问题，本文提出基于正余弦变换和双调滤波相结合的剪切散斑干涉图像去噪方法。该方法首先对相位条纹图进行正余弦变换获得两幅图像，其次对这两幅图像分别运用双调滤波方法进行去噪，最后将滤波后的两幅图像合并为最终的相位条纹图。实验结果表明：经本文方法滤波后的相位图散斑抑制指数为0.999，平均保持指数为2.995，证明该方法较传统去噪方法能更好地改善相位图质量，且能较大程度地保留相位条纹的细节及边缘信息。

An impact structure 1400 m in diameter, formed by a bolide impact, has been discovered on Baijifeng Mountain in Tonghua City in Northeast China’s Jilin province. The impact structure takes the form of a cirque-shaped depression on the top of the mountain and is located in a basement mainly composed of Proterozoic sandstone and Jurassic granite. A large number of rock fragments composed mainly of sandstone, with a small amount of granite, are distributed on the top of Baijifeng Mountain. Planar deformation features (PDFs) have been found in quartz in the rock and mineral clasts collected from the surface inside the depression. The forms of the PDFs indexed in the quartz include among others, {101̄3}, {101̄2}, and {101̄1}. The presence of these PDFs provides diagnostic evidence for shock metamorphism and the impact origin of the structure. The impact event took place after the Jurassic Period and probably much later.

We developed a general framework for parallel all-optical logic operations with independent phase control of arbitrary orthogonal polarization state enabled by a single-layer metasurface. A pair of orthogonal circular polarized bases are used as two input channels of the logic operator, and their four combinations perfectly match various binary input states. Correspondingly, distinct phase profiles are encoded into the metasurface, which enables parallel operation of the two logic gates by way of polarization switching. It allows for an efficient and compact way to implement multi-channel multiplexed logic gate operations with the capability of fast optical computing at the chip scale.

As a newly discovered type of structured light, a spatiotemporal optical vortex (STOV), which is remarkable for its space–time spiral phase and transverse orbital angular momentum (OAM), has garnered substantial interest. Most previous studies have focused on the generation, characterization, and propagation of STOVs, but their nonlinear frequency conversion remains largely unexplored. Here, we experimentally demonstrate the generation of green and ultraviolet (UV) STOVs by frequency upconversion of a STOV carried near-infrared (NIR) pulse emitted by a high repetition rate Yb-doped fiber laser amplifier system. First, we verify that the topological charge of spatiotemporal OAM (ST-OAM) is doubled along with the optical frequency in the second-harmonic generation (SHG) process, which is visualized by the diffraction patterns of the STOVs in the fundamental and second-harmonic field. Second, the space–time characteristic of NIR STOV is successfully mapped to UV STOV by sum-frequency mixing STOV at 1037 nm and Gaussian beams in the green band. Furthermore, we observe the topological charges of the ST-OAM could be degraded owing to strong space–time coupling and complex spatiotemporal astigmatism of such beams. Our results not only deepen our understanding of nonlinear manipulation of ST-OAM spectra and the generation of STOVs at a new shorter wavelength, but also may promote new applications in both classical and quantum optics.

基于光纤受激布里渊散射的布里渊光纤激光器以其Hz量级甚至亚Hz量级的超窄线宽特性，自问世以来便吸引了广泛的研究关注。超窄线宽布里渊光纤激光器主要经历三个发展阶段，从最初的基于单模光纤谐振腔的布里渊光纤激光器，到向腔内引入掺铒光纤放大器的布里渊掺铒光纤激光器，再到利用一段普通掺铒光纤同时提供布里渊增益与线性增益的紧凑型布里渊掺铒光纤激光器，激光器的性能不断得到发展，相关理论研究也不断得到丰富。近10年，紧凑型布里渊掺铒光纤激光器的研究取得了一系列的进展，在高精度光纤传感等诸多领域有着十分重要的应用前景。按照三个发展阶段依次梳理和总结了布里渊光纤激光器的研究进展，重点阐述了紧凑型布里渊掺铒光纤激光器的机理、特性和应用，并对其未来发展方向进行展望。

为了提升车道线检测算法在障碍物遮挡等复杂情况下的检测性能，本文提出了一种基于双注意力机制的多车道线检测算法。首先，本文通过设计基于空间和通道双注意力机制的车道线语义分割网络，得到分别代表车道线像素和背景区域的二值分割结果；然后，引入HNet网络结构，使用其输出的透视变换矩阵将分割图转换为鸟瞰视图，继而进行曲线拟合并逆变换回原图像空间，实现多车道线的检测；最后，将图像中线两侧车道线所包围的区域定义为目前行驶的行车车道。本文算法在Tusimple数据集凭借134 frame/s的实时性表现达到了96.63%的准确率，在CULane数据集取得了77.32%的精确率。实验结果表明，本文算法可以针对包括障碍物遮挡等不同场景下的多条车道线及行车车道进行实时检测，其性能相比较现有算法得到了显著的提升。