Author Affiliations
Abstract
1 State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China.
2 Chongqing Key Laboratory of Precision Optics, Chongqing Institute of East China Normal University, Chongqing 401120, China.
3 Shanghai Key Lab of Modern Optical System, University of Shanghai for Science and Technology, Shanghai 200093, China.
4 Jinan Institute of Quantum Technology, Jinan, China.
Breakdown spectroscopy is a valuable tool for determining elements in solids, liquids, and gases. All materials in the breakdown region can be ionized and dissociated into highly excited fragments and emit characteristic fluorescence spectra. In this sense, the elemental composition of materials can be evaluated by detecting the fluorescence spectrum. This paper reviews the recent developments in laser-induced breakdown spectroscopy. The traditional laser-induced breakdown spectroscopy, filament-induced breakdown spectroscopy, plasma grating, and multidimensional plasma grating-induced breakdown spectroscopy are introduced. There are also some proposals for applications of plasma gratings, such as laser ablation, laser deposition, and laser catalysis of chemical reactions in conjunction with research on the properties of plasma gratings.
Ultrafast Science
2023, 3(1): 0013
封接玻璃是一种用于连接、密封同种或异种材料的特种玻璃。近年来多种类、高质量金属间封接需求递增,要求开发更高膨胀系数的封接玻璃。详细介绍了线膨胀系数高于90×10-7 ℃-1的封接玻璃的国内外研究现状,分析了高膨胀系数封接玻璃的发展趋势。无铅结晶型封接玻璃可以达到更高的线膨胀系数,足以适配常用金属,无铅封接玻璃综合性能不亚于含铅封接玻璃,能够实现对含铅封接玻璃的替代,具有更大的发展优势。
封接玻璃 高膨胀系数 无铅结晶型封接玻璃 sealing glass high expansion coefficient lead-free crystalline sealing glass
上海交通大学电子信息与电气工程学院,上海 200240
针对当前高光谱分类算法难以同时满足星载分类高精度、低能耗需求的问题,提出一种基于多尺度空间特征提取的高光谱星载分类算法,在保持较高分类精度的同时大幅度降低算法的计算开销。利用局部最大值滤波提取高光谱图像的纹理特征,将多尺度滤波结果根据遥感图像空间关联性进行组合得到局部-全局联合空间特征,融合空间特征和光谱特征后采用随机森林进行分类。该算法仅包含整数比较和加法运算,未采用高光谱主流分类算法中的乘法和求幂等高开销运算。在Indian Pines、Pavia University和HyRANK影像数据集上的实验结果表明,该算法与最高水平分类算法相比分类精度损失保持在2.4%以内,在跨场景分类中同样获得了较高的分类精度,与星载分类算法相比分类过程能耗降低到1/10000以下。该算法与现有算法相比更适用于星载分类任务,能够在保持较高分类精度的同时有效降低星载分类过程中的计算开销和能耗。
图像处理 高光谱图像 星载分类 多尺度空间特征 计算能耗优化 激光与光电子学进展
2023, 60(10): 1010004
Author Affiliations
Abstract
1 State Key Laboratory of Digital Manufacturing Equipment and Technology, Huazhong University of Science and Technology, Wuhan 430074, People’s Republic of China
2 School of Astronautics, Harbin Institute of Technology, Harbin 150001, People’s Republic of China
3 Department of Biomedical Engineering, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, People’s Republic of China
The growing demand for electronic devices, smart devices, and the Internet of Things constitutes the primary driving force for marching down the path of decreased critical dimension and increased circuit intricacy of integrated circuits. However, as sub-10 nm high-volume manufacturing is becoming the mainstream, there is greater awareness that defects introduced by original equipment manufacturer components impact yield and manufacturing costs. The identification, positioning, and classification of these defects, including random particles and systematic defects, are becoming more and more challenging at the 10 nm node and beyond. Very recently, the combination of conventional optical defect inspection with emerging techniques such as nanophotonics, optical vortices, computational imaging, quantitative phase imaging, and deep learning is giving the field a new possibility. Hence, it is extremely necessary to make a thorough review for disclosing new perspectives and exciting trends, on the foundation of former great reviews in the field of defect inspection methods. In this article, we give a comprehensive review of the emerging topics in the past decade with a focus on three specific areas: (a) the defect detectability evaluation, (b) the diverse optical inspection systems, and (c) the post-processing algorithms. We hope, this work can be of importance to both new entrants in the field and people who are seeking to use it in interdisciplinary work.
optical defect inspection microscopy nanophotonics integrated circuits deep learning International Journal of Extreme Manufacturing
2022, 4(3): 032001
上海理工大学 光电信息与计算机工程学院, 上海 200093
针对激光切片技术缺少重频可调激光光源, 设计了一种脉冲平均功率35.4W, 脉宽12ps, 重复频率300kHz~1MHz可调的高功率掺镱光纤皮秒脉冲激光器。激光器采用全光纤振荡器及预放大系统, 配合基于棒状光子晶体光纤的主放大系统, 并通过在级联放大中加入声光调制器(AOM)调控重复频率, 从而实现重复频率可调的高功率皮秒脉冲输出。激光器振荡器及预放大部分的全光纤设计, 相较于空间耦合放大具有光路结构简单、环境稳定性高等特点, 有望推动高能量飞秒光纤激光工业化进程, 提升其在复杂使用环境的适应性。
光纤光学 超短脉冲 高功率激光 光子晶体光纤 棒状光纤 optical fiber1 ultrashort pulse2 high power laser3 photonic crystal fiber4 rod fiber5
1 上海理工大学 光电信息与计算机工程学院,上海 200093
2 华东师范大学 精密光谱科学与技术国家重点实验室,上海 200062
3 济南量子技术研究院,山东 济南 250101
4 华东师范大学 重庆研究院,重庆 401121
利用反射式太赫兹时域光谱研究飞秒光激发狄拉克半金属五碲化锆表面产生的瞬态光电流,进而分析五碲化锆产生太赫兹辐射的几种物理过程。实验结果表明,偏振无关的光电流是表面电流的主要成分,同时太赫兹振幅与泵浦脉冲的线偏振相关,表明部分电流产生于非线性光整流效应。圆偏振光泵浦下,太赫兹振幅随泵浦脉冲呈四倍周期性变化,证实五碲化锆在飞秒脉冲泵浦下产生圆偏振光电流效应。进一步分析超短激光脉冲激发下的太赫兹时域电场,揭示五碲化锆在光诱导下发生反演对称性破缺,产生B1u声子,形成瞬态外尔点,发生从狄拉克态到外尔态的转变。这对研究拓扑相变和其他拓扑态等方面具有重要意义。
太赫兹光谱 狄拉克材料 五碲化锆 圆偏光电流效应 terahertz spectroscopy Dirac materials ZrTe5 circular photogalvanic effect
上海理工大学光电信息与计算机工程学院,上海 200093
高重复频率光纤激光器因其光斑质量好、集成化程度高、光光转化率高等优势在光学频率梳、工业加工、超高速光学采样等领域有着举足轻重的作用。利用非线性偏振旋转(NPR)的锁模机理,设计并搭建了一款基础重复频率为163 MHz的“十字腔”型孤子锁模光纤飞秒激光器。该激光器锁模后在450 mW的泵浦功率下可以输出200 mW的最大功率,光谱半高宽为30 nm,输出脉宽为786 fs。通过进一步分析激光器泵浦功率与输出功率之间的关系,得到泵浦功率处于400~500 mW时,激光器处于最佳锁模状态,并且可以实现自启动锁模。所设计的激光器由于其更加紧密的光学频率梳齿、更好的成像质量和更快的成像速度,在精密光谱、天文探测等领域具有应用意义。
光纤激光器 非线性偏振旋转 高重复频率 fiber laser nonlinear polarization rotation high repetition frequency
红外与激光工程
2022, 51(4): 20220171
光子学报
2021, 50(11): 1130001