宁波大学机械工程与力学学院，浙江 宁波 315211
数字图像相关法作为一种直接有效的非接触、全场光学测量方法，已广泛地应用于各个领域材料和结构的二维/三维位移和应变测量。结合先进的散斑制备技术，在显微镜下进行原位加载实验，可实现微尺度数字图像相关位移和应变测量。微尺度下试样加载过程中将不可避免地出现离面位移，由于光学显微镜景深限制，微小的离面位移将导致散斑图像失焦模糊，从而为变形测量带来相应的误差。为减小这种失焦模糊带来的误差，采用盲去卷积方法对散斑图像去模糊，并针对噪声问题采用高斯滤波的方法对散斑图像进行去噪，定量分析了图像复原对数字图像相关测量精度的影响，并对indium tin oxide（ITO）薄膜进行了拉伸实验。实验结果表明，图像复原后测量的弹性模量误差减小了13.91%，应变测量结果的精度与稳定性更高。
图像处理 数字图像相关 图像复原 噪声去除 微尺度 变形测量 激光与光电子学进展
2023, 60(14): 1410004
华中师范大学 化学学院, 农药与化学生物学教育部重点实验室, 武汉 430079
电催化二氧化碳还原反应可将温室气体二氧化碳转化为化工原料或者有机燃料, 为克服全球变暖和电能向化学能转化提供了一条可行途径。该技术的主要挑战是产物分布广, 导致单一产物选择性低, 而调控催化剂的表面性质是解决这一难题的可行策略。本研究通过对氧化亚铜、硫化亚铜进行氧化制备表面性质不同的氧化铜, 其中, 氧化硫化亚铜制得的CuO-FS催化剂提高了电还原二氧化碳的活性和还原产物甲酸的选择性。该催化剂表现出较高的总电流密度, 而且在一个较大的测试电压范围(-0.8 ~ -1.1 V)内, 甲酸的法拉第效率可以保持在70%以上, 在-0.9 V时达到最大值78.4%。反应机理探究表明, CuO-FS优异的电还原二氧化碳性能归因于其较大的电化学活性表面积提供了大量表面活性位点, 产生较高的总电流密度; 而且电催化过程中催化剂表面产生较少的零价Cu, 减少了乙烯的生成, 使产物更集中于甲酸。
电还原二氧化碳 铜基催化剂 表面性质 产物选择性 甲酸 CO2 electroreduction Cu-based catalyst surface properties product selectivity formic acid
1 江苏大学机械工程学院, 江苏 镇江 212000
2 常州星宇车灯股份有限公司, 江苏 常州 213000
为使汽车在夜间行驶时能够被别的车辆识别, 避免交通事故的发生, 设计了聚光器带有花纹的新型后位置灯光学系统。基于非成像光学理论, 采用照度优化方法, 利用公式计算自由曲面反射镜各个点的坐标值。根据法规对后位置灯的配光要求, 合理划分反射面, 使其达到配光要求。通过蒙特卡洛方法对光线进行追迹, 实验模拟结果显示: 配光效果达到国家标准GB5920-2008对后位置灯各个测试点的照度要求, 设计的新型结构使光型出光更加均匀, 避免了亮斑的产生。
光源 聚光器 自由曲面反射面 后位置灯 亮斑 配光标准 light source concentrator free-form reflective surface rear position light bright spot light distribution standard
吉林大学 电子科学与工程学院 集成光电子学国家重点实验室, 吉林 长春 130012
喷墨打印作为一种非接触式、无需掩膜的数字印刷技术, 被广泛应用于印刷电路板、光伏组件和显示器件等领域。近年来, 金属卤化物钙钛矿作为一种新型的直接带隙离子型半导体材料, 受到科研工作者们的广泛关注与研究。利用喷墨打印技术可以对钙钛矿墨滴的分配和沉积过程进行精确调控, 为钙钛矿光电器件迈向产业化提供了一种可行的工艺路线。本文从喷墨打印的工作原理出发, 分别从墨水制备和打印工艺两个角度概述了喷墨打印钙钛矿光电器件的发展进程, 并分析了目前喷墨打印钙钛矿所面临的挑战。同时对基于喷墨打印技术制备钙钛矿光电器件的功能层和电极进行了总结, 在此基础上对喷墨打印钙钛矿光电器件未来的发展前景和产业化探索进行了展望。
喷墨打印 钙钛矿发光器件 钙钛矿太阳能电池 inkjet printing perovskite luminescent device perovskite solar cells
Author Affiliations
Abstract
1 College of Computer, National University of Defense Technology, Changsha 410073, China
2 College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha 410073, China
3 National Innovation Institute of Defense Technology, Academy of Military Sciences PLA China, Beijing 100071, China
4 Beijing Institute for Advanced Study, National University of Defense Technology, Beijing 100020, China
5 Hefei Interdisciplinary Center, National University of Defense Technology, Hefei 230037, China
The application of machine learning to the field of ultrafast photonics is becoming more and more extensive. In this paper, for the automatic mode-locked operation in a saturable absorber-based ultrafast fiber laser (UFL), a deep-reinforcement learning algorithm with low latency is proposed and implemented. The algorithm contains two actor neural networks providing strategies to modify the intracavity lasing polarization state and two critic neural networks evaluating the effect of the actor networks. With this algorithm, a stable fundamental mode-locked (FML) state of the UFL is demonstrated. To guarantee its effectiveness and robustness, two experiments are put forward. As for effectiveness, one experiment verifies the performance of the trained network model by applying it to recover the mode-locked state with environmental vibrations, which mimics the condition that the UFL loses the mode-locked state quickly. As for robustness, the other experiment, at first, builds a database with UFL at different temperatures. It then trains the model and tests its performance. The results show that the average mode-locked recovery time of the trained network model is 1.948 s. As far as we know, it is 62.8% of the fastest average mode-locked recovery time in the existing work. At different temperatures, the trained network model can also recover the mode-locked state of the UFL in a short time. Remote algorithm training and automatic mode-locked control are proved in this work, laying the foundation for long-distance maintenance and centralized control of UFLs.
Photonics Research
2021, 9(8): 08001493
Author Affiliations
Abstract
1 College of Computer, National University of Defense Technology, Changsha 410073, China
2 National Innovation Institute of Defense Technology, Beijing 100010, China
3 Graduate School, National University of Defense Technology, Changsha 410073, China
Recently reported plasmon-induced transparency (PIT) in metamaterials endows the optical structures in classical systems with quantum optical effects. In particular, the nonreconfigurable nature in metamaterials makes multifunctional applications of PIT effects in terahertz communications and optical networks remain a great challenge. Here, we present an ultrafast process-selectable modulation of the PIT effect. By incorporating silicon islands into diatomic metamaterials, the PIT effect is modulated reversely, depending on the vertical and horizontal configurations, with giant modulation depths as high as 129% and 109%. Accompanied by the enormous switching of the transparent window, remarkable slow light effect occurs.
terahertz metamaterials ultrafast photoswitching plasmon-induced transparency all-optical modulation Chinese Optics Letters
2021, 19(1): 013602
Author Affiliations
Abstract
1 School of Electronic Science and Engineering (National Exemplary School of Microelectronics), University of Electronic Science and Technology of China, Chengdu 611731, P. R. China
2 Center for Information in Medicine, University of Electronic Science and Technology of China, Chengdu 611731, P. R. China
3 Department of Medical Engineering, University of South Florida, Tampa 33620, USA
We present a systematical study on comparison between water and dry coupling in photoacoustic tomography of the human finger joints. Compared to the direct water immersion of the finger for water coupling, the dry coupling is realized through a transparent PDMS film-based water bag, which ensures water-free contact with the skin. The results obtained suggest that the dry coupling provides image quality comparable to that by water coupling while eliminating the wrinkling of the finger joint caused by the water immersion. In addition, the dry coupling offers more stable hemodynamic images than the water coupling as the water immersion of the finger joint causes reduction in blood vessel size.
Photoacoustic tomography dry coupling water coupling finger joints Journal of Innovative Optical Health Sciences
2020, 13(4): 2050008
Author Affiliations
Abstract
1 School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu, Sichuan, P. R. China
2 Center for Information in Biomedicine, University of Electronic Science and Technology of China, Sichuan, P. R. China
3 School of Physics, University of Electronic Science and Technology of China, Chengdu, Sichuan, P. R. China
4 Department of Medical Engineering, University of South Florida, Tampa, FL 33620, USA
In this study, we developed a novel photoacoustic imaging technique based on poly (ethyleneglycol)-coated (PEGylated) gold nanorods (PEG-GNRs) (as the contrast agent) combined with traditional Chinese medicine (TCM) acupuncture (as the auxiliary method) for quantitatively monitoring contrast enhancement in the vasculature of a mouse brain in vivo. This study takes advantage of the strong near-infrared absorption (peak at ~700 nm) of GNRs and the ability to adjust the hemodynamics of acupuncture. Experimental results show that photoacoustic tomography (PAT) successfully reveals the optical absorption variation of the vasculature of the mouse brain in response to intravenous administration of GNRs and acupuncture at the Zusanli acupoint (ST36) both individually and combined. The quantitative measurement of contrast enhancement indicates that the composite contrast agents (integration of acupuncture and GNRs) would greatly enhance the photoacoustic imaging contrast. The quantitative results also have the potential to estimate the local concentration of GNRs and even the real-time effects of acupuncture.
Photoacoustic tomography acupuncture contrast agent nanorods Zusanli acupoint Journal of Innovative Optical Health Sciences
2019, 12(3): 1941004
南方科技大学 电子与电气工程系，广东 深圳 518055
作为一种新兴的纳米材料，CdSe/CdS 量子棒的偏振发光特性使其在应用于新型液晶显示中极具潜力，而如何将量子棒材料在宏观尺度上大面积的定向排列是实现该技术的关键性问题。在本文中，我们报道了一种大面积、含定向排列量子棒、基于PMMA纳米纤维制成的偏振增亮膜。首先，采用一种新的TBP辅助合成方法，合成出具有核壳结构的CdSe/CdS量子棒。该材料的绝对量子产率达到了60%，发光波长的半峰宽为25 nm，具有182 nm的大Stokes位移。随后将这些量子棒溶于氯仿、DMF和PMMA混合溶液中制备用于静电纺丝的纺丝液。通过静电纺丝技术，将含有量子棒的聚合物纳米纤维通过滚筒收集处理，得到了一张透明、大面积、偏振增强的增亮膜， 5 cm2 增亮膜的偏振度为0.45。最后将制备的增亮膜嵌入一个液晶显示模组中测试，结果显示该模组的亮度提高了18.4%。这一结果表明我们制备的量子棒增亮膜在新型宽色域高光效显示领域具有非常广阔的应用前景。
量子棒 偏振 静电纺丝 定向排列 quantum rods polarization electrospinning alignment
