周妃四 1,2李时春 1,2,*陈曦 3蔡文靖 1,2[ ... ]周磊 1,2
作者单位
摘要
1 湖南科技大学 难加工材料高效精密加工湖南省重点实验室,湘潭 411201
2 湖南科技大学 机电工程学院,湘潭 411201
3 上汽大众汽车有限公司长沙分公司,长沙 410000
激光增材制造过程的工艺参数直接影响成型件的成形质量及性能,对工艺参数的优化是实现成形质量调控的最有效方法。建立准确、高精度的工艺参数与成形质量之间的模型,对于成形质量的预测及工艺参数的优选极其重要。对激光增材制造工艺参数优化建模的方法进行了总结和综述,且对工艺系统开发进行了现状分析,论述了工艺优化建模方法的原理以及优缺点,最后对激光增材制造工艺优化建模研究前景进行了展望。
激光技术 优化建模 工艺参数 工艺系统 增材制造 laser technique optimization model process parameters process system additive manufacturing 
激光技术
2023, 47(4): 469
作者单位
摘要
1 北方信息控制研究院集团有限公司,江苏南京 210000
2 驻南京地区第三军事代表室,江苏南京 210000
针对跨海桥梁或沿海机场等场所需要实时测算获取移动船只目标绝对位置和高程的现实需要,文中介绍一种高精度光电船只目标定位系统设计与实现方案。通过将高清高精度光学探测组件集成于高精度云台设备内部,可实时解算出目标点的绝对位置信息和高程信息并上报监控系统。结合雷达系统引导可实现无人值守情况下自动测算过往船只经纬度坐标及高程功能。经实际运行测试,该系统展现出良好的可靠性,具有较好的测量精度和应用前景。
光学探测组件 云台 无人值守 自动测算 经纬度坐标 高程 optical detection assembly, PTZ, unattended, autom 
红外技术
2023, 45(10): 1090
作者单位
摘要
1 复旦大学信息科学与工程学院,上海超精密光学制造工程技术研究中心,上海 200433
2 复旦大学物理学系,应用表面物理国家重点实验室,上海 200433
片上光场 表面波 远场辐射 超构表面 on-chip optical fields surface wave far-field radiation metasurface 
光电工程
2023, 50(8): 230173
Sheng Zhang 1,2†Yongwei Cui 1,2,3Shunjia Wang 1,2Haoran Chen 1,2,3[ ... ]Zhensheng Tao 1,2,*
Author Affiliations
Abstract
1 Fudan University, State Key Laboratory of Surface Physics, Department of Physics, Shanghai, China
2 Fudan University, Key Laboratory of Micro and Nano Photonic Structures, Shanghai, China
3 Shanghai Research Center for Quantum Sciences, Shanghai, China
4 Beijing Normal University, Center for Advanced Quantum Studies, Department of Physics, Beijing, China
5 Fudan University, Institute for Nanoelectronic Devices and Quantum Computing, Shanghai, China
Precise and ultrafast control over photo-induced charge currents across nanoscale interfaces could lead to important applications in energy harvesting, ultrafast electronics, and coherent terahertz sources. Recent studies have shown that several relativistic mechanisms, including inverse spin-Hall effect, inverse Rashba–Edelstein effect, and inverse spin-orbit-torque effect, can convert longitudinally injected spin-polarized currents from magnetic materials to transverse charge currents, thereby harnessing these currents for terahertz generation. However, these mechanisms typically require external magnetic fields and exhibit limitations in terms of spin-polarization rates and efficiencies of relativistic spin-to-charge conversion. We present a nonrelativistic and nonmagnetic mechanism that directly utilizes the photoexcited high-density charge currents across the interface. We demonstrate that the electrical anisotropy of conductive oxides RuO2 and IrO2 can effectively deflect injected charge currents to the transverse direction, resulting in efficient and broadband terahertz radiation. Importantly, this mechanism has the potential to offer much higher conversion efficiency compared to previous methods, as conductive materials with large electrical anisotropy are readily available, whereas further increasing the spin-Hall angle of heavy-metal materials would be challenging. Our findings offer exciting possibilities for directly utilizing these photoexcited high-density currents across metallic interfaces for ultrafast electronics and terahertz spectroscopy.
terahertz optics ultrafast science nanophotonics 
Advanced Photonics
2023, 5(5): 056006
史晋芳 1邱荣 2,*郭德成 2周磊 2[ ... ]谢准 2
作者单位
摘要
1 西南科技大学 制造过程测试技术教育部重点实验室,四川 绵阳 621010
2 西南科技大学 极端条件物质特性联合实验室,四川 绵阳 621010
利用Nd:YAG激光器研究了DKDP晶体元件在激光辐照下的表面损伤特性,对比研究了355 nm和1064 nm激光辐照下晶体元件的表面损伤形貌,分析了每种损伤形貌对应的前驱体和损伤机制。研究结果表明:相对于体损伤,晶体的表面损伤更加复杂,在脉宽约10 ns、损伤概率小于等于50%的激光能量密度辐照下,DKDP晶体的表面损伤主要有带坑底空腔损伤坑、表面损伤裂纹、平底损伤坑、表面烧蚀四种典型形貌。通过光学显微镜和扫描电子显微镜的成像和分析发现:带坑底空腔损伤坑和表面损伤裂纹的前驱体都是晶体体缺陷,平底损伤坑的前驱体则可能是表面加工裂纹、裂纹内碎屑、表层体缺陷等中的一种或多种,表面烧蚀主要由表面污染和浅表层缺陷形成。与熔石英光学元件一样,表面损伤仍然是晶体元件抗激光辐照损伤的薄弱环节。
激光诱导表面损伤 DKDP晶体 损伤形貌 材料体缺陷 表面加工缺陷 laser-induced surface damage DKDP crystal damage morphology material bulk defect surface processing defect 
强激光与粒子束
2023, 35(7): 071003
Author Affiliations
Abstract
1 State Key Laboratory of Surface Physics, Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education) and Department of Physics, Fudan University, Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education) and Department of Physics, 200433 Shanghai, People’s Republic of China
2 Academy for Engineering and Technology, Fudan University, Fudan University, 200433 Shanghai, People’s Republic of China
3 Collaborative Innovation Center of Advanced Microstructures, 210093, 210093 Nanjing, People’s Republic of China
Freely switching light transmission and absorption via an achromatic reflectionless screen is highly desired for many photonic applications (e.g., energy-harvesting, cloaking, etc.), but available meta-devices often exhibit reflections out of their narrow working bands. Here, we rigorously demonstrate that an optical metasurface formed by two resonator arrays coupled vertically can be perfectly reflectionless at all frequencies below the first diffraction mode, when the near-field (NF) and far-field (FF) couplings between two constitutional resonators satisfy certain conditions. Tuning intrinsic loss of the system can further modulate the ratio between light transmission and absorption, yet keeping reflection diminished strictly. Designing/fabricating a series of metasurfaces with different inter-resonator configurations, we experimentally illustrate how varying inter-resonator NF and FF couplings can drive the system to transit between different phase regions in a generic phase diagram. In particular, we experimentally demonstrate that a realistic metasurface satisfying the discovered criteria exhibits the desired achromatic reflectionless property within 160–220 THz (0–225 THz in simulation), yet behaving as a perfect absorber at ~ 203 THz. Our findings pave the road to realize meta-devices exhibiting designable transmission/absorption spectra immune from reflections, which may find many applications in practice.
PhotoniX
2023, 4(1): 3
Author Affiliations
Abstract
Fudan University, Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education) and Department of Physics, State Key Laboratory of Surface Physics, Shanghai, China
Dynamically controlling terahertz (THz) waves with an ultracompact device is highly desired, but previously realized tunable devices are bulky in size and/or exhibit limited light-tuning functionalities. Here, we experimentally demonstrate dynamic modulation on THz waves with a dielectric metasurface in mode-selective or mode-unselective manners through pumping the system at different optical wavelengths. Quasi-normal-mode theory reveals that the physics is governed by the spatial overlap between wave functions of resonant modes and regions inside resonators perturbed by pump laser excitation at different wavelengths. We further design/fabricate a dielectric metasurface and experimentally demonstrate that it can dynamically control the polarization state of incident THz waves, dictated by the strength and wavelength of the pumping light. We finally numerically demonstrate pump wavelength-controlled optical information encryption based on a carefully designed dielectric metasurface. Our studies reveal that pump light wavelength can be a new external knob to dynamically control THz waves, which may inspire many tunable metadevices with diversified functionalities.
dynamic metasurfaces terahertz quasi-normal-mode theory optical pumping 
Advanced Photonics
2023, 5(2): 026005
廖大松 1汪倩 1王非森 1,2陈辉 1,*[ ... ]周磊 2
作者单位
摘要
1 西南交通大学材料科学与工程学院,四川 成都 610031
2 成都交大智辉激光科技有限公司,四川 彭州611936

采用纳秒脉冲激光器对TC4钛合金表面的氧化膜及油污进行激光清洗,研究了扫描速度对清洗后试样表面形貌、成分、元素含量及价态的影响规律,并分析了扫描速度对表面粗糙度、硬度和耐腐蚀性能的影响。结果表明:当扫描速度为500 mm/s时,激光对基体的损伤大且会发生热氧化,表面形成TiO,O含量较高。随着扫描速度由3000 mm/s增加至10000 mm/s,表面逐渐变得光滑平整,O含量先降低后升高,Ti含量则先升高后降低。当扫描速度为9000 mm/s时,表面Ti含量(质量分数)达到最大值84.24%,O含量(质量分数)降至最小值4.54%,且粗糙度(Ra)最低约为0.907 μm,清洗效果最佳。扫描速度的增加使清洗后表面的粗糙度先升高后降低。此外,激光清洗可使TC4钛合金表面的硬度和耐腐蚀性能有所提高。

激光技术 激光清洗 钛合金氧化膜 表面形貌 化学成分 粗糙度 电化学腐蚀 laser technique laser cleaning titanium alloy oxide film surface morphology chemical composition roughness electrochemical corrosion 
中国激光
2023, 50(4): 0402020
Author Affiliations
Abstract
1 State Key Laboratory of Surface Physics and Department of Physics, Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education), Fudan University, Shanghai 200433, China
2 Shanghai Engineering Research Centre of Ultra-Precision Optical Manufacturing, Green Photonics and Department of Optical Science and Engineering, Fudan University, Shanghai 200433, China
Metasurfaces have exhibited great capabilities to control electromagnetic waves, and many multifunctional metasurfaces were recently proposed. However, although angle-multiplexed meta-devices were successfully realized in reflection geometries, their transmission-mode counterparts are difficult to achieve due to the additional requirements. Here, we design and fabricate a transmissive angle-multiplexed meta-polarizer in the microwave regime based on a multilayer metasurface. Coupled-mode-theory analyses reveal that the device exhibits distinct angle-dependent transmissive responses under excitations with different polarizations, and such differences are further enhanced by multiple scatterings inside the device. Microwave experimental results are in good agreement with numerical simulations and theoretical analyses.
metasurfaces angular dispersion multifunctional meta-device polarization modulation 
Chinese Optics Letters
2023, 21(2): 023603
作者单位
摘要
1 黑龙江省农业科学院土壤肥料与环境资源研究所, 黑龙江 哈尔滨 150086
2 中国农业科学院农业资源与农业区划研究所/耕地培育技术国家工程实验室/农业部植物营养与肥料重点实验室, 北京 100081
3 北京农林科学院植物营养与资源研究所, 北京 100097
4 黑龙江省科学院微生物研究所, 黑龙江 哈尔滨 150001
5 农业农村部环境保护科研监测所, 天津 300191
土壤有机碳是农业生态系统的关键驱动和调节者, 特别是根际微域有机碳动态对土壤碳素循环和矿质营养元素释放起着重要作用。 研究长期不同化肥和有机肥施用下大豆根际土壤有机碳、 活性有机碳以及有机碳结构的变化规律, 深入了解根际有机碳固持和稳定机制, 为完善农田生态系统碳固持和农田可持续发展提供科学依据和理论支撑。 该研究依托黑土长期定位试验, 采用化学分析、 固态13C-核磁共振 (13C-NMR)等方法研究大豆根际土壤有机碳含量、 活性有机碳含量和有机碳结构组分变化规律。 结果表明, 与非根际土壤相比, 大豆根际土壤有机碳含量显著增加, 长期施肥处理能够显著增加根际土壤有机碳和低活性有机碳含量, 以常量有机肥加氮磷钾(MNPK)处理提升效果最好。 核磁共振实验结果表明, 与不施肥处理相比, MNPK处理明显增加根际土壤烷基碳、 烷氧基碳比例以及烷基碳/烷氧基碳比值, 降低芳香基碳和芳香碳/总碳比值, 在非根际土壤中尤其显著; 常量氮磷钾(NPK)处理增加芳香基碳比例和芳香碳/总碳比值, 在根际土壤中烷基碳比例和烷基碳/烷氧基碳比值增加, 烷氧基碳比例降低, 非根际土壤测试结果相反。 综上所述, MNPK处理能够显著提升根际有机碳含量, 增加有机碳中烷基碳、 烷氧基碳比例以及烷基碳/烷氧基碳比值, 促进团聚体形成和增加土粒结构稳定性, 而NPK处理增加芳香基碳比例和芳香碳/总碳比值, 降低根际烷氧基碳比例, 团聚体稳定性降低, 同时证明固态13C-核磁共振技术结合半定量分析能够准确地分析不同有机碳结构组分变化, 深刻认识根际土壤有机碳的稳定机制。
有机碳 大豆根际 黑土 13C-核磁共振 Soil organic carbon Soybean rhizosphere Black soil 13C-NMR 
光谱学与光谱分析
2022, 42(12): 3883

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