强激光与粒子束
2024, 36(4): 043025
1 山西大学 激光光谱研究所 量子光学与光量子器件国家重点实验室, 山西 太原 030006
2 山西大学 极端光学协同创新中心, 山西 太原 030006
3 中石油化工股份有限公司石油化工科学研究院, 北京 100083
4 中国兵器科学研究院, 北京 100089
5 山西新华防化装备研究院有限公司, 山西 太原 030041
6 西安工业大学 光电工程学院, 陕西 西安 710021
7 山西格盟中美清洁能源研发中心有限公司, 山西 太原 030032
为了消除激光诱导击穿光谱技术(laser-induced breakdown spectroscopy,LIBS)中的自吸收效应,提高元素定量分析的精确度,同时满足工业中便捷分析元素的要求,需将自吸收免疫激光诱导击穿光谱技术(self-absorption free laser-induced breakdown spectroscopy,SAF-LIBS)的装置小型化。本文提出了一项新型的高重频声光门控SAF-LIBS定量分析技术,使用高重频激光器产生准连续的等离子体以增强光谱强度,并将声光调制器(acousto-optic modulator,AOM)作为门控开关,从而使微型CCD光谱仪和AOM能够代替传统大型SAF-LIBS装置中的像增强探测器(intensified charge coupled device,ICCD)和中阶梯型光栅光谱仪,实现自吸收免疫的同时缩小了装置的体积,降低了装置的成本。将该系统参数进行优化选择后,对样品中的Al元素进行了定量分析和预测。实验结果表明,等离子体的特性受激光重复频率的影响进而会影响光谱信号的强度。在1 ~ 50 kHz激光重复频率范围内,Al I 394.4 nm和Al I 396.15 nm的双线强度先增强后减弱,确定最佳的激光重复频率为10 kHz。在不同的光纤采集角度下,Al的双线强度比随延迟时间的增加而减小,在45°处信噪比最高,且在一定的积分时间下,最佳光学薄时间tot为426 ns。在激光重复频率为10 kHz、光纤采集角为45°、延迟时间为400 ns的条件下,对Al元素进行定量分析和预测结果表明,Al元素定标曲线的线性度R2为0.982,平均绝对测量误差相对于单一LIBS的0.8%可以降低至0.18%。定量分析结果与传统大型SAF-LIBS装置的测量精度相持平。因此本高重频声光门控SAF-LIBS装置不仅有效地屏蔽了光学厚等离子体中的连续背景辐射和谱线加宽,同时具备小型化、低成本、高可靠性的优点,有助于推动SAF-LIBS技术由实验室走向工业应用。
激光诱导击穿光谱 自吸收免疫 光学薄 高重频激光器 声光门控 laser-induced breakdown and spectroscopy self-absorption free optically thin high repetition rate laser acousto-optic gating
长光卫星技术股份有限公司,吉林 长春 130033
为解决传统柔性支撑中小口径空间反射镜组件热稳定性与结构刚度间的矛盾,提出了一种新型刚性支撑结构,并为某高分辨率空间相机研制了通光口径?214 mm的高精度次镜组件。采用“镜体-锥套-支撑筒-刚性基板”组合,通过延长、优化热应力在组件内部的传递路径实现了消热目的。刚性支撑次镜组件重2.6 kg、4 ℃均匀温升工况下面形变化均方根(RMS)仿真值为2.573 nm,装调重力工况下镜体倾角和位移分别为2.028″、0.566 μm,与传统柔性支撑方案相比具有突出的优势。实测次镜的面形精度RMS为0.0181λ(λ=632.8 nm),在16 ℃及24 ℃时次镜面形变化量不超过0.0025λ;组件基频达到502.1 Hz,在快速高低温循环及大量级振动后次镜面形基本维持不变;装配容差测试中,次镜在0.02 mm不平度的作用下仅发生微弱变形。刚性支撑结构可以显著提升中小口径反射镜工作性能,在遥感器光机结构研制领域内具有广阔的应用前景。
空间光学 反射镜 刚性支撑 消热 面形精度稳定性 激光与光电子学进展
2024, 61(5): 0522005
Author Affiliations
Abstract
1 Interdisciplinary Center for Quantum Information, New Cornerstone Science Laboratory, State Key Laboratory of Extreme Photonics and Instrumentation, College of Optical Science and Engineering, Zhejiang University, Hangzhou, China
2 Jiaxing Key Laboratory of Photonic Sensing & Intelligent Imaging, Intelligent Optics & Photonics Research Center, Jiaxing Research Institute Zhejiang University, Jiaxing, China
3 Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, China
An optical micro/nanofiber (MNF) is a quasi-one-dimensional free-standing optical waveguide with a diameter close to or less than the vacuum wavelength of light. Combining the tiny geometry with high-refractive-index contrast between the core and the surrounding, the MNF exhibits favorable optical properties such as tight optical confinement, strong evanescent field, and large-diameter-dependent waveguide dispersion. Meanwhile, as a quasi-one-dimensional structure with extraordinarily high geometric and structural uniformity, the MNF also has low optical loss and high mechanical strength, making it favorable for manipulating light on the micro/nanoscale with high flexibility. Over the past two decades, optical MNFs, typically being operated in single mode, have been emerging as a miniaturized fiber-optic platform for both scientific research and technological applications. In this paper, we aim to provide a comprehensive overview of the representative advances in optical MNFs in recent years. Starting from the basic structures and fabrication techniques of the optical MNFs, we highlight linear and nonlinear optical and mechanical properties of the MNFs. Then, we introduce typical applications of optical MNFs from near-field optics, passive optical components, optical sensors, and optomechanics to fiber lasers and atom optics. Finally, we give a brief summary of the current status of MNF optics and technology, and provide an outlook into future challenges and opportunities.
micro/nanofibers fabrication optical properties mechanical properties optical applications Photonics Insights
2024, 3(1): R02
Author Affiliations
Abstract
1 School of Information Science and Technology, Fudan University, Shanghai 200433, China
2 Changfei Optical Fiber and Cable Joint Stock Limited Company, Wuhan 430073, China
3 Nanjing University of Information Science & Technology, Nanjing 210000, China
We experimentally transmit eight wavelength-division-multiplexing (WDM) channels, 16 quadratic-amplitude-modulation (QAM) signals at 32-GBaud, over 1000 km few mode fiber (FMF). In this experiment, we use WDM, mode division multiplexing, and polarization multiplexing for signal transmission. Through the multiple-input–multiple-output (MIMO) equalization algorithms, we achieve the total line transmission rate of 4.096 Tbit/s. The results prove that the bit error rates (BERs) for the 16QAM signals after 1000 km FMF transmission are below the soft-decision forward-error-correction (SD-FEC) threshold of , and the net rate reaches 3.413 Tbit/s. Our proposed system provides a reference for the future development of high-capacity communication.
optical fiber communication mode division multiplexing few-mode fiber multiple-input–multiple-output high-capacity transmission long-distance transmission Chinese Optics Letters
2024, 22(1): 010602
Author Affiliations
Abstract
1 Key Laboratory of Opto-electronic Information Acquisition and Manipulation, Ministry of Education, Anhui University, Hefei 230601, China
2 Information Materials and Intelligent Sensing Laboratory of Anhui Province, Anhui University, Hefei 230601, China
An imperfect propagation environment or optical system would introduce wavefront aberrations to vortex beams. The phase aberrations and orbital angular momentum in a vortex beam are proved to be mutually restrictive in parameter measurement. Aberrations make traditional topological charge (TC) probing methods ineffective while the phase singularity makes phase retrieval difficult due to the aliasing between the wrapped phase jump and the vortex phase jump. An interactive probing method is proposed to make measurements of the aberrated phase and orbital angular momentum in a vortex beam assist rather than hinder each other. The phase unwrapping is liberated from the phase singularity by an annular shearing interference technique while the TC value is determined by a Moiré technique immune to aberrations. Simulation and experimental results proving the method effective are presented. It is of great significance to judge the characteristics of vortex beams passing through non-ideal environments and optical systems.
Photonics Research
2024, 12(1): 172
Author Affiliations
Abstract
1 Research Center for Humanoid Sensing, Zhejiang Lab, Hangzhou 311100, China
2 State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, Zhejiang University, Hangzhou 310027, China
Friction plays a critical role in dexterous robotic manipulation. However, realizing friction sensing remains a challenge due to the difficulty in designing sensing structures to decouple multi-axial forces. Inspired by the topological mechanics of knots, we construct optical fiber knot (OFN) sensors for slip detection and friction measurement. By introducing localized self-contacts along the fiber, the knot structure enables anisotropic responses to normal and frictional forces. By employing OFNs and a change point detection algorithm, we demonstrate adaptive robotic grasping of slipping cups. We further develop a robotic finger that can measure tri-axial forces via a centrosymmetric architecture composed of five OFNs. Such a tactile finger allows a robotic hand to manipulate human tools dexterously. This work could provide a straightforward and cost-effective strategy for promoting adaptive grasping, dexterous manipulation, and human-robot interaction with tactile sensing.
robotic perception adaptive grasping slip detection force decoupling polymer optical fiber Opto-Electronic Advances
2023, 6(10): 230076
中国人民解放军63963部队, 北京 100072
受限于材料和制造工艺, 红外图像中普遍存在着条纹非均匀性, 其严重影响了图像的成像效果, 进而对后续的目标识别、检测等工作造成干扰。典型的最小均方误差(LMS)算法在一定程度上可以抑制条纹非均匀性, 但其场景适应性差, 存在拖尾和“鬼影”现象。提出一种改进型的最小均方误差(LMS)自适应滤波算法对图像进行处理, 利用双边滤波和最速下降法快速获取准确的校正参数, 将前一帧算出的校正结果作为后一帧的初始输入值, 提升算法的准确性, 同时算法还增加了边缘检测模块以保留图像细节。采用不同场景下非制冷型探测器的真实红外图像, 从主观和客观两个方面对比了本算法和经典LMS算法, 结果表明, 提出的算法可以很好地保护图像细节, 也具有良好的场景适应性。
红外图像 条纹非均匀性 最小均方误差 边缘检测 自适应滤波 infrared thermal image stripe nonuniformity least-mean-square error edge detection adaptive filtering