Author Affiliations
Abstract
1 Laboratory of Infrared Materials and Devices, Research Institute of Advanced Technologies, Ningbo University, Ningbo 315211, China
2 Engineering Research Center for Advanced Infrared Photoelectric Materials and Devices of Zhejiang Province, Ningbo University, Ningbo 315211, China
3 Department of Quantum Science and Technology, Research School of Physics, Australian National University, Canberra ACT 2601, Australia
4 School of Physics and Optoelectronics Engineering, Xidian University, Xi’an 710071, China
Three-dimensional (3D) nonlinear photonic crystals have received intensive interest as an ideal platform to study nonlinear wave interactions and explore their applications. Periodic fork-shaped gratings are extremely important in this context because they are capable of generating second-harmonic vortex beams from a fundamental Gaussian wave, which has versatile applications in optical trapping and materials engineering. However, previous studies mainly focused on the normal incidence of the fundamental Gaussian beam, resulting in symmetric emissions of the second-harmonic vortices. Here we present an experimental study on second-harmonic vortex generation in periodic fork-shaped gratings at oblique incidence, in comparison with the case of normal incidence. More quasi-phase-matching resonant wavelengths have been observed at oblique incidence, and the second-harmonic emissions become asymmetric against the incident beam. These results agree well with theoretic explanations. The oblique incidence of the fundamental wave is also used for the generation of second-harmonic Bessel beams with uniform azimuthal intensity distributions. Our study is important for a deeper understanding of nonlinear interactions in a 3D periodic medium. It also paves the way toward achieving high-quality structured beams at new frequencies, which is important for manipulation of the orbital angular momentum of light.
second-harmonic generation nonlinear photonic crystal periodically poled ferroelectric crystal quasi-phase matching nonlinear wavefront shaping Chinese Optics Letters
2024, 22(4): 041902
刘译泽 1,2,3江俊峰 1,2,3,*刘琨 1,2,3王双 1,2,3[ ... ]刘铁根 1,2,3
1 天津大学精密仪器与光电子工程学院，天津 300072
2 天津大学光电信息技术教育部重点实验室，天津 300072
3 天津大学光纤传感研究所，天津 300072
提出了基于氧化石墨烯和空心二氧化硅薄壁微泡腔的光纤气体传感器。将氧化石墨烯涂覆于熔融加压流变成型的薄壁微泡腔内壁，使其整体的有效折射率对于气体吸附敏感。通过拉锥光纤倏逝场在薄壁微泡腔激发出回音壁谐振模，其中心波长与有效折射率（气体体积分数）对应，据此实现腔内气体体积分数的传感测量。实验结果表明，当氨气的体积分数在0~40×10-6的范围内时，提出的光纤气体传感器的响应呈线性，其传感灵敏度为0.73×106 pm，分辨率为1.9×10-6。当氨气的体积分数为20×10-6时，传感器的响应和恢复时间分别是294 s和329 s。空心微腔结构一方面可以作为敏感单元，另一方面可以直接作为气体通道，避免了外部气室的使用或额外气体通道的封装，极大地提高了传感系统的实用性。
传感器 气体传感器 回音壁谐振模 氧化石墨烯 
Author Affiliations
Abstract
1 Aerospace Laser Technology and Systems Department, CAS Key Laboratory of Materials for High-Power Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
2 Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
3 CAS Center for Excellence in Ultra-intense Laser Science (CEULS), State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
4 e-mail: n.n.dong@siom.ac.cn
Since the emergence of graphene, transition metal dichalcogenides, and black phosphorus, two-dimensional materials have attracted significant attention and have driven the development of fundamental physics and optoelectronic devices. Metal phosphorus trichalcogenides (), due to their large bandgap of 1.3–3.5 eV, enable the extension of optoelectronic applications to visible and ultraviolet (UV) wavelengths. Micro-Z/I-scan (-Z/I-scan) and micro-pump-probe (-pump-probe) setups were used to systematically investigate the third-order nonlinear optical properties and ultrafast carrier dynamics of the representative material . UV-visible absorption spectra and density functional theory (DFT) calculations revealed a quantum confinement effect, in which the bandgap decreased with increasing thickness. The two-photon absorption (TPA) effect is exhibited under the excitation of both 520 and 1040 nm femtosecond pulses, where the TPA coefficient decreases as the thickness increases. In contrast, the TPA saturation intensity exhibits the opposite behavior that the TPA saturation is more likely to occur under visible excitation. After the valence band electrons undergo photon transitions to the conduction band, the non-equilibrium carriers relax through non-radiative and defect-assisted recombination. These findings provide a comprehensive understanding of the optical response process of and are a valuable reference for the development of optoelectronic devices.
Photonics Research
2024, 12(4): 691
细胞内存在大量性质各异的大分子复合物，它们是控制生命活动的核心信号枢纽。荧光显微成像因其分子特异性、细胞原位可视化和多色标记解析等优势，已成为当今生物学研究不可或缺的技术手段。而突破光学衍射极限的超分辨光学成像技术为进一步理解多种重要生物百纳米信号体的原位结构和功能调节提供了亚细胞尺度甚至单分子精度的研究思路和方案。首先阐述了超分辨成像和单分子定位显微镜的基本原理，介绍了近年来在多项生命科学研究中的代表性应用案例，结合实际研究经验总结了超分辨光学成像技术在使用中面临的诸多挑战和未来发展方向，提出了基于原位纳米成像解析信号枢纽组织结构将有力促进新型疾病治疗靶点和策略的开发。
生物光学 超分辨成像 单分子定位 生物信号体 信号转导
为实现复杂工况下焊接机器人精准识别焊缝目标, 将激光视觉传感技术应用于机器人焊缝识别中。以激光视觉传感器作为核心硬件, 构建焊接图像采集系统, 运用PCI总线卡检测传感器及外部指示灯是否为连接状态, 通过PXR800图像采集卡在规定时间内得到激光焊接图像, 使用串口通信程序完成图像高效传输。分别采用双边滤波器与模糊算子实施图像去噪与增强处理, 优化图像角点与激光条纹中心点, 利用等式约束方程修正卡尔曼滤波后的图像坐标值, 完成高精度焊缝识别任务。仿真结果证明, 激光视觉传感能够帮助机器人提升焊缝识别精度、增强抗干扰能力, 为焊接机器人的推广应用发挥积极作用。
激光视觉传感 焊接机器人 焊缝识别 图像采集 卡尔曼滤波 laser vision sensing welding robot weld identification image acquisition Kalman filtering
广西公安计算机通讯技术研究所，广西南宁 530001
针对大多数基于 GAN的红外与可见光图像融合方法仅在生成器使用注意力机制，而鉴别阶段缺乏注意力感知能力的问题，提出了一种基于双注意力机制生成对抗网络（double attention generative adversarial networks,DAGAN）的红外与可见光图像融合方法。 DAGAN提出一种多尺度注意力模块，该模块在不同尺度空间中将空间注意力和通道注意力结合，并将其应用在图像生成阶段和鉴别阶段，使生成器和鉴别器均能感知图像中最具鉴别性的区域，同时提出了一种注意力损失函数，利用鉴别阶段的注意力图计算注意力损失，保存更多目标信息和背景信息。公开数据集 TNO测试表明：与其他 7种融合方法相比， DAGAN具有最好的视觉效果与最高的融合效率。
红外与可见光图像融合 公安应用 注意力机制 生成器 鉴别器 infrared and visible image fusion, public security GAN
Author Affiliations
Abstract
1 School of Physical Science and Technology, ShanghaiTech University, 393 Middle Huaxia Road, Shanghai 201210, People’s Republic of China
2 State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Laboratory of Advanced Materials, Fudan University, Shanghai 200433, People’s Republic of China
3 School of Textile and Clothing, Yancheng Institute of Technology, Jiangsu 224051, People’s Republic of China
4 School of Textile Science and Engineering, Wuhan Textile University, Wuhan 430200, People’s Republic of China
5 Shanghai Clinical Research and Trial Center, 201210, Shanghai, People’s Republic of China
This study proposes a rational strategy for the design, fabrication and system integration of the humanoid intelligent display platform (HIDP) to meet the requirements of highly humanized mechanical properties and intelligence for human–machine interfaces. The platform's sandwich structure comprises a middle light-emitting layer and surface electrodes, which consists of silicon elastomer embedded with phosphor and silk fibroin ionoelastomer, respectively. Both materials are highly stretchable and resilient, endowing the HIDP with skin-like mechanical properties and applicability in various extreme environments and complex mechanical stimulations. Furthermore, by establishing the numerical correlation between the amplitude change of animal sounds and the brightness variation, the HIDP realizes audiovisual interaction and successful identification of animal species with the aid of Internet of Things (IoT) and machine learning techniques. The accuracy of species identification reaches about 100% for 200 rounds of random testing. Additionally, the HIDP can recognize animal species and their corresponding frequencies by analyzing sound characteristics, displaying real-time results with an accuracy of approximately 99% and 93%, respectively. In sum, this study offers a rational route to designing intelligent display devices for audiovisual interaction, which can expedite the application of smart display devices in human–machine interaction, soft robotics, wearable sound-vision system and medical devices for hearing-impaired patients.
Nano-Micro Letters
2023, 15(1): 221
1 浙江理工大学基础结构技术研究所, 杭州 310018
2 浙江省装配式混凝土工业化建筑工程技术研究中心, 杭州 310018
为提高工业废渣的利用率, 选用磷石膏、高炉矿渣、硅酸钠代替部分水泥并对土样进行固化处理。通过D-最优混料设计, 得出3与7 d的无侧限抗压强度回归方程, 并计算得到最优质量配合比。使用最优配方固化土样, 测得3和7 d无侧限抗压强度分别达4.88和5.84 MPa。通过因素间交互分析结果, 得出固化材料的最优掺量范围。通过X射线衍射和扫描电子显微镜对固化土微观机理进行分析, 结果表明最优固化土相比水泥固化土水化反应更完全, 颗粒间连接更密实, 结构更稳定。最后通过对最优配方进行环境效益与经济性评价, 得出该配方在强度、环境效益、经济性等方面均要优于水泥。
工业废渣 早强固化剂 D-最优混料设计 最优配合比 无侧限抗压强度 微观机理 industrial waste residue early strength curing agent D-optimal mixture design optimal mixture ratio unconfined compression strength microscopic mechanism
1 南京航空航天大学自动化学院, 南京 210000
2 中国人民解放军95791部队,甘肃 酒泉 735000
提出一种基于传感器网络的分布式状态估计算法, 用于具有随机传输时延的网络化系统。为了节省通信带宽, 引入了自适应概率量化机制。考虑随机传输时延的存在, 利用缓存器中的数据设计了改进的无迹卡尔曼滤波(UKF)算法进行时延补偿。在局部估计完成后, 利用快速协方差交叉方法进行融合估计, 以获取更加精确的状态估计。此外, 还分析了融合估计误差的有界性。最后通过数值模拟算例验证了所提算法的有效性。
传感器网络 分布式状态估计 概率量化 时延 无迹卡尔曼滤波 sensor network distributed state estimation probability quantization time delay UKF
