Optics and Laser Technology最新文献_第8页

Simultaneous measurement of temperature by Background-oriented Schlieren and speckle interferometry: Comparison and validation 利用背景导向 Schlieren 和斑点干涉仪同时测量温度：比较与验证

IF 4.6 2区物理与天体物理 Q1 OPTICS

Optics and Laser Technology

Pub Date : 2024-11-20 DOI: 10.1016/j.optlastec.2024.112161

Siyuan Fang, Zhongfang Gao, Bicheng Guo, Brian Sangeorzan, Lianxiang Yang

The application of Background-oriented Schlieren (BOS) technology for measuring air flow temperatures is becoming increasingly popular due to its simplicity and practicality. However, there is still a lack of synchronous experimental measurement techniques to verify its measurement accuracy. Electronic Speckle Pattern Interferometry (ESPI), as a high-precision measurement technique, is currently being employed in the field of temperature field measurements. In this study, to verify the accuracy of BOS, an innovative optical setup was designed to achieve the synchronous measurement of temperature field by BOS and ESPI. A plate is set in the object beam path of ESPI, and the laser is irradiated on the plate to form a BOS measurement laser speckle background pattern, which forms a BOS measurement system with the camera. The two measurement systems can simultaneously capture speckle patterns before and after the hot air flow field is introduced into the optical path, enabling the calculation of air temperature. This approach avoids errors that may arise from slight variations in the flow field when comparing results from non-synchronous measurements. The quality of the laser speckle is optimized by adjusting the aperture, beam expander and laser power. The measurement accuracy, uncertainty and sensitivity of BOS are evaluated in the reconstruction of the temperature field of the hot air flow above the alcohol lamp flame. The results show that the temperature field measured by BOS is consistent with the temperature field measured by speckle interferometry, and its measurement sensitivity is related to the flow field position and the focal length of the camera.

面向背景的 Schlieren（BOS）技术因其简单实用，在气流温度测量中的应用日益普及。然而，目前仍缺乏同步实验测量技术来验证其测量精度。电子斑点模式干涉仪（ESPI）作为一种高精度测量技术，目前正在温度场测量领域得到应用。在这项研究中，为了验证 BOS 的精度，设计了一种创新的光学装置，以实现 BOS 和 ESPI 同步测量温度场。在 ESPI 的目标光束路径上设置一块平板，激光照射在平板上形成 BOS 测量激光斑点背景图案，与相机组成 BOS 测量系统。两个测量系统可同时捕捉热气流场进入光路前后的斑点图，从而计算出空气温度。这种方法可以避免在比较非同步测量结果时因流场的微小变化而产生误差。通过调整光圈、扩束器和激光功率，可以优化激光斑点的质量。在重建酒精灯火焰上方热气流的温度场时，对 BOS 的测量精度、不确定性和灵敏度进行了评估。结果表明，BOS 测量的温度场与斑点干涉仪测量的温度场一致，其测量灵敏度与流场位置和相机焦距有关。

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引用次数: 0

Low current driven blue-violet light-emitting diodes based on p-GaN/i-Ga2O3/n-Ga2O3:Si structure 基于 p-GaN/i-Ga2O3/n-Ga2O3:Si 结构的低电流驱动型蓝紫色发光二极管

IF 4.6 2区物理与天体物理 Q1 OPTICS

Optics and Laser Technology

Pub Date : 2024-11-20 DOI: 10.1016/j.optlastec.2024.112173

Wenwen Jin , Xian Zhang , Guojiao Xiang , Zhiang Yue , Enqin Zhao , Shuaikang Wei , Jingwen Shu , Hangyu He , Meibo Xin , Fujing Dong , Yang Zhao , Hui Wang

This paper reports a low current driven LED with p-GaN/i-Ga₂O₃/n-Ga₂O₃:Si structure prepared by radio frequency (RF) magnetron sputtering, the driving current of the device is only 0.02 mA. Compared with the reported drive current of the LEDs, the reduction is 100 or even 1000 times. Through the study of its electrical properties, it was found that it had excellent rectification characteristics at different ambient temperatures and the turn-on voltage was about 1.8 V. In addition, the leakage current was as low as 4.30 × 10^-8 mA. Through the electroluminescence test, it was found that the device had the function of emitting in the ultraviolet (363 nm) and visible (425 nm) region, which realized the blue-violet luminescence at room temperature. Furthermore, the device had excellent high temperature color stability and ultra-low color temperature of 1924 K. The color coordinate of the device at room temperature was (0.1905,0.0955). A detailed study was conducted on the electroluminescence mechanism of the device through its band structure, and the causes of the luminescence were analyzed through the Gaussian fitting of the EL spectrum.

本文报道了一种采用射频（RF）磁控溅射法制备的 p-GaN/i-Ga2O3/n-Ga2O3:Si 结构的低电流驱动 LED，该器件的驱动电流仅为 0.02 mA。与所报道的 LED 驱动电流相比，降低了 100 甚至 1000 倍。通过对其电学特性的研究发现，它在不同环境温度下都具有出色的整流特性，开启电压约为 1.8 V，而且漏电流低至 4.30 × 10-8 mA。通过电致发光测试发现，该器件具有在紫外（363 纳米）和可见光（425 纳米）区域发光的功能，实现了室温下的蓝紫色发光。此外，该器件还具有极佳的高温色稳定性和 1924 K 的超低色温，室温下的色坐标为（0.1905,0.0955）。研究人员通过该器件的能带结构对其电致发光机理进行了详细研究，并通过电致发光光谱的高斯拟合分析了发光原因。

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引用次数: 0

Process study of picosecond laser welding of soda-lime glass 钠钙玻璃皮秒激光焊接工艺研究

IF 4.6 2区物理与天体物理 Q1 OPTICS

Optics and Laser Technology

Pub Date : 2024-11-19 DOI: 10.1016/j.optlastec.2024.112095

Yichen Huang , Zihao Zhang , Xu Wang , Liqun Li , Lijun Yang , Mingyu Li , Wenbo Zhu

The various excellent properties of glass make it widely used in aerospace, solar cells and other fields, and its processing methods have also attracted much attention. Ultra-fast laser has the characteristics of high peak energy density and low heat impact, which has unique advantages in welding of transparent materials such as glass. At this stage, most of the ultra-fast laser welding is carried out for the glass with optical contact, and the harsh optical contact conditions hinder the further application of glass welding technology. In this paper, an attempt is made to weld non-optical contacted soda-lime glass using high repetition frequency infrared picosecond laser. The effects of laser power, scanning times, scanning spacing, scanning direction and focus position on weld morphology and breaking strength were systematically investigated. The results show that the scanning times and scanning spacing affect the volume of glass melt on one hand, and the stress magnitude during the welding process on the other hand, which have a greater impact on the overall weld strength. Under the optimal process parameters, an effective connection can be achieved within ± 200 μm of the defocusing amount, and the weld formed has a size of 10 mm × 5 mm. A strength of 24.85 MPa is obtained when the force direction is perpendicular to the scanning direction. The mechanism of glass welding was finally revealed, providing technical guidance for the practical application of ultrafast laser welding of glass.

玻璃的各种优异性能使其广泛应用于航空航天、太阳能电池等领域，其加工方法也备受关注。超快激光具有峰值能量密度高、热冲击小等特点，在玻璃等透明材料的焊接方面具有独特的优势。现阶段，超快激光焊接大多是针对有光学接触的玻璃进行的，苛刻的光学接触条件阻碍了玻璃焊接技术的进一步应用。本文尝试使用高重复频率红外皮秒激光焊接非光学接触的钠钙玻璃。系统研究了激光功率、扫描时间、扫描间距、扫描方向和聚焦位置对焊缝形态和断裂强度的影响。结果表明，扫描时间和扫描间距一方面会影响玻璃熔体的体积，另一方面会影响焊接过程中的应力大小，而这两者对整体焊接强度的影响更大。在最佳工艺参数下，可在离焦量的± 200 μm 范围内实现有效连接，形成的焊缝尺寸为 10 mm × 5 mm。当受力方向与扫描方向垂直时，可获得 24.85 兆帕的强度。最终揭示了玻璃焊接的机理，为玻璃超快激光焊接的实际应用提供了技术指导。

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引用次数: 0

Gaussian mixture model based invalid point removal for fringe projection profilometry 基于高斯混合物模型的条纹投影轮廓测量无效点去除技术

IF 4.6 2区物理与天体物理 Q1 OPTICS

Optics and Laser Technology

Pub Date : 2024-11-19 DOI: 10.1016/j.optlastec.2024.112077

Huixin Song, Lingbao Kong, Qiyuan Wang

In fringe projection profilometry, there inevitably exist many invalid points in the background and the occluded region that are not covered by the fringe pattern. The reconstruction result of invalid points is wrong, which seriously degrades the quality of the reconstructed point cloud and thus affects the measurement accuracy. Therefore, recognizing and removing invalid points is necessary. In this paper, an adaptive invalid point removal method based on Gaussian mixture model (GMM) is innovatively proposed for fringe projection profilometry (FPP). The proposed approach firstly calculates the modulation level using multistep phase-shifting method. Secondly, GMM is applied to model the density distribution of the modulation information and thus classify the pixels based on the modulation information. Thirdly, the classification results are further optimized using absolute phase gradient information and neighborhood information. Then the final classification results of the modulation intensity and the corresponding invalid point identification results can be obtained. A series of experimental results demonstrated that the method can accurately identify invalid points and improve the quality of point cloud reconstruction under different measurement scenarios.

在边缘投影轮廓测量中，背景和遮挡区域不可避免地存在许多未被边缘图案覆盖的无效点。无效点的重建结果是错误的，这会严重降低重建点云的质量，从而影响测量精度。因此，识别和去除无效点很有必要。本文针对边缘投影轮廓仪（FPP）创新性地提出了一种基于高斯混合模型（GMM）的自适应无效点去除方法。所提方法首先使用多步移相法计算调制电平。其次，应用 GMM 对调制信息的密度分布进行建模，从而根据调制信息对像素进行分类。第三，利用绝对相位梯度信息和邻域信息进一步优化分类结果。然后就可以得到调制强度的最终分类结果和相应的无效点识别结果。一系列实验结果表明，该方法能在不同的测量场景下准确识别无效点，并提高点云重建的质量。

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引用次数: 0

A continuous plane of polarization rotator and detector based on the liquid crystal Θ-cell 基于液晶Θ电池的连续平面偏振旋转器和检测器

IF 4.6 2区物理与天体物理 Q1 OPTICS

Optics and Laser Technology

Pub Date : 2024-11-19 DOI: 10.1016/j.optlastec.2024.112138

Deepak Kararwal, Rahul Panchal, Aloka Sinha

Modulation of the polarization state of optical beams is crucial in advanced optical applications such as polarization microscopy, polarization rotation, and medical imaging. We demonstrate a continuous polarization rotator (PR) by utilizing the liquid crystals (LC) in Θ-cell configuration comprising of circular and parallel alignment of LC on two aligning glass substrates. A rotation of plane of polarization (PoP) up to ∼ 160˚ is observed using Stokes polarimetry. This is further substantiated by the mathematical analysis using Mueller matrix formalism. Further, the device is demonstrated as a PoP detector with high precision detection angle. The PoP is analyzed through single-shot imaging of the intensity distribution of transmitted light through the LC Θ-cell.

在偏振显微镜、偏振旋转和医学成像等先进光学应用中，调制光束的偏振状态至关重要。我们展示了一种连续偏振旋转器（PR），它利用液晶（LC）在两个对齐玻璃基板上的环形和平行排列组成的 Θ-Cell 配置。通过斯托克斯偏振测量法，观察到偏振平面（PoP）的旋转可达 ∼ 160˚。使用穆勒矩阵形式的数学分析进一步证实了这一点。此外，该装置还被证明是具有高精度探测角的 PoP 探测器。通过对穿过 LC Θ-Cell 的透射光的强度分布进行单次成像，对 PoP 进行了分析。

引用次数: 0

Improved surface quality components enabled by dual-laser additive/subtractive hybrid manufacturing process: Thermal behavior and ablation mechanisms 利用双激光增材/减材混合制造工艺提高部件表面质量：热行为和烧蚀机制

IF 4.6 2区物理与天体物理 Q1 OPTICS

Optics and Laser Technology

Pub Date : 2024-11-19 DOI: 10.1016/j.optlastec.2024.112147

Donghua Dai , Zhiheng Xia , Yuhang Long , Han Zhang , Jianye Liu , Zhenghua Huang , Keyu Shi

A high roughness of the laser powder bed fusion (LPBF) process has been one of the most concerned issues in the integrated fabrication of complicated metal parts. In this research, a dual (continuous and ultrafast) laser additive-subtractive hybrid manufacturing (LASHM) process is introduced to improve the surface quality of the LPBF-processed components. Effects of the laser subtractive times and the feed rates on the side surface morphology of the LASHM-processed AISI 316L components were studied. Meanwhile, the VOF transient physical model of LPBF and double temperature physical model of LASHM were established to investigate the individual thermal behaviors and the material melting-ablation mechanisms. For the LPBF process, the operating temperature of the molten pool bottom was firstly stable in 300 K (< 25 ms), then increased to 630 K (25 ms-35 ms) and finally exponentially increased to 3000 K (>35 ms), implying the delayed thermal effect. Meanwhile, the operating temperature of the top region was linearly increased to 2050 K. While for the ultrafast laser subtractive process, the operating temperature of the top region was remained at ∼ 300 K with the temperature rapid increase to 2900 K below 10⁴ ps in the bottom region, leading to the direct material ablation and maintaining the LPBF-processed microstructure. At the laser subtractive times equal to four with the sequence feed rates of 10 μm, 10 μm, 8 μm and 6 μm, the surface roughness Sa and the maximum surface height difference Sz were considerably reduced from 10.774 μm and 73.387 μm to 1.933 μm and 18.151 μm.

激光粉末床熔融（LPBF）工艺的高粗糙度一直是复杂金属零件集成制造中最受关注的问题之一。本研究引入了一种双（连续和超快）激光增材减材混合制造（LASHM）工艺，以改善 LPBF 加工部件的表面质量。研究了激光减法时间和进给量对 LASHM 加工的 AISI 316L 零件侧表面形貌的影响。同时，建立了 LPBF 的 VOF 瞬态物理模型和 LASHM 的双温物理模型，研究了各自的热行为和材料熔融烧蚀机理。在 LPBF 过程中，熔池底部的工作温度首先稳定在 300 K（25 ms），然后上升到 630 K（25 ms-35 ms），最后指数上升到 3000 K（35 ms），这意味着延迟热效应。而在超快激光减法过程中，顶部区域的工作温度保持在 300 K 左右，底部区域的温度在 104 ps 以下迅速升高到 2900 K，导致材料直接烧蚀并保持 LPBF 加工的微观结构。在 10 μm、10 μm、8 μm 和 6 μm 的顺序进给速率下，激光减法次数等于 4 时，表面粗糙度 Sa 和最大表面高度差 Sz 从 10.774 μm 和 73.387 μm 显著降低到 1.933 μm 和 18.151 μm。

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引用次数: 0

Microstructures and mechanical properties of pure copper manufactured by high-strength laser powder bed fusion 利用高强度激光粉末床熔融技术制造的纯铜的微观结构和机械性能

IF 4.6 2区物理与天体物理 Q1 OPTICS

Optics and Laser Technology

Pub Date : 2024-11-18 DOI: 10.1016/j.optlastec.2024.112134

Yi Wei , Genyu Chen , Zhikang Xiao , Yi Zhang , Yunlong Zhou , Xufei Liu , Wei Li , Jianbo Xu

Pure copper is widely used in motor windings, heat exchangers and aerospace engines because of its high electrical and thermal conductivity. High-strength laser powder bed fusion (HS-LPBF) not only allows rapid production of components with complex geometry and high spatial resolution, but also offers various advantages such as small focal spot diameter, fine powder, and small layer thickness, providing advantages for forming complex structural parts in fields such as engines and heat exchangers. A single factor single layer experiment was performed by varying the hatch spacing (H), and the range of hatch spacing was determined according to the overlap rate. The degree of influence of process parameters on the relative density of pure copper specimens was analyzed using an orthogonal experiment, and a comparative study of the phase composition, microstructure and mechanical properties of pure copper specimens was carried out by varying the laser power. The characteristics of pure copper formed by HS-LPBF were analyzed. In addition, the effect of heat treatment on the microstructure and mechanical properties of pure copper specimens was investigated, and the fracture morphology of the specimens was observed comparatively. The results show that the HS-LPBF technique can effectively increase the energy density and improve the specific surface area of the powder and the laser absorptivity due to its small focal spot diameter, fine powder and layer thickness, thus reducing the minimum energy required to melt pure copper powder. The optimum process parameters were obtained by orthogonal experiment with a relative density of 98.1 % of the specimen. The highest hardness, ultimate tensile strength and elongation were obtained at a laser power of 260 W with 84 HV, 320 MPa and 17.8 %, respectively. This ultimate tensile strength is 18 % higher than the highest ultimate tensile strength that has been reported so far. In addition, the average grain size of the optimal specimens was 3.6 µm. Mechanical properties such as hardness, tensile strength and elongation of pure copper parts can be significantly improved by precisely controlling the process parameters, in particular laser power and hatch spacing.

纯铜具有很高的导电性和导热性，因此被广泛应用于电机绕组、热交换器和航空发动机。高强度激光粉末熔床（HS-LPBF）不仅能快速生产几何形状复杂、空间分辨率高的部件，还具有焦斑直径小、粉末细、层厚小等多种优势，为发动机和热交换器等领域复杂结构部件的成型提供了有利条件。通过改变舱口间距（H）进行了单因素单层实验，并根据重叠率确定了舱口间距的范围。利用正交实验分析了工艺参数对纯铜试样相对密度的影响程度，并通过改变激光功率对纯铜试样的相组成、微观结构和机械性能进行了对比研究。分析了 HS-LPBF 所形成的纯铜的特性。此外，还研究了热处理对纯铜试样微观结构和力学性能的影响，并比较观察了试样的断口形貌。结果表明，HS-LPBF 技术由于焦斑直径小、粉末细、层厚薄，可以有效提高能量密度，改善粉末比表面积和激光吸收率，从而降低熔化纯铜粉末所需的最小能量。通过正交实验获得了最佳工艺参数，试样的相对密度为 98.1%。在激光功率为 260 W、电压为 84 HV 时，获得的硬度、极限拉伸强度和伸长率最高，分别为 320 MPa 和 17.8 %。这一极限抗拉强度比目前已报道的最高极限抗拉强度高出 18%。此外，最佳试样的平均晶粒大小为 3.6 微米。通过精确控制工艺参数，特别是激光功率和舱口间距，纯铜零件的硬度、抗拉强度和伸长率等机械性能都能得到显著改善。

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引用次数: 0

Rapid optimization of iron-based alloy laser cladding process based on orthogonal experiment and machine learning for Q345 基于正交实验和机器学习的 Q345 铁基合金激光熔覆工艺快速优化

IF 4.6 2区物理与天体物理 Q1 OPTICS

Optics and Laser Technology

Pub Date : 2024-11-18 DOI: 10.1016/j.optlastec.2024.112086

Yi Zhang , Peikang Bai , Zhonghua Li , Jie Zhang

The properties of laser cladding coatings are closely correlated with process parameters. The laser power (P), scanning speed (V_S), and powder feeding rate(V_F) were optimized to enhance the comprehensive properties of laser cladding iron-based alloy single coating on Q345, with a focus on achieving targets such as dilution rate (η), aspect ratio (W/H), and hardness (H_D) of single coating. Firstly, the impact of process parameters on coating properties were analyzed through orthogonal experiments. Subsequently, prediction models between process parameters and coating properties were established by using back propagation neural network(BPNN), which optimized by particle swarm optimization(PSO) and Genetic Algorithm(GA). Finally, non-dominated sorting genetic algorithm II(NSGA-II) was employed to optimize the process parameters, and the optimized results were verified and analyzed. The findings indicate that laser power is the primary factor influencing dilution rate and hardness, while powder feeding rate primarily affects aspect ratio. The optimized process parameters include a laser power of 934 W, scanning speed of 352 mm/min, powder feeding rate of 0.64r/min, corresponding aspect ratio of 3.06, hardness of 613HV, dilution rate of 0.33. There were no obvious defects in the coating and the coating hardness was three times higher than that of the substrate. The optimization results of orthogonal experiments are constrained by the process range, fortunately, the utilization of machine learning optimization methods can effectively address these limitations and avoid the re-experiment due to improper settings in orthogonal experiments. It offers a rapid and efficient method for optimizing laser cladding process parameters.

激光熔覆涂层的性能与工艺参数密切相关。通过优化激光功率（P）、扫描速度（VS）和送粉速率（VF），提高了 Q345 铁基合金激光熔覆单层涂层的综合性能，重点实现了单层涂层的稀释率（η）、长宽比（W/H）和硬度（HD）等目标。首先，通过正交实验分析了工艺参数对涂层性能的影响。随后，利用反向传播神经网络（BPNN）建立了工艺参数与涂层性能之间的预测模型，并通过粒子群优化（PSO）和遗传算法（GA）进行了优化。最后，采用非支配排序遗传算法 II（NSGA-II）对工艺参数进行了优化，并对优化结果进行了验证和分析。研究结果表明，激光功率是影响稀释率和硬度的主要因素，而送粉率则主要影响长宽比。优化后的工艺参数包括：激光功率为 934 W，扫描速度为 352 mm/min，送粉速度为 0.64r/min，相应的长宽比为 3.06，硬度为 613HV，稀释率为 0.33。涂层无明显缺陷，涂层硬度是基体的三倍。正交实验的优化结果受到工艺范围的限制，幸运的是，利用机器学习优化方法可以有效解决这些限制，避免正交实验中因设置不当而导致的重新实验。它为优化激光熔覆工艺参数提供了一种快速高效的方法。

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引用次数: 0

Enhanced three-channel dual-polarization silicon photonic balanced receiver for long-range FMCW laser ranging systems 用于远距离 FMCW 激光测距系统的增强型三通道双偏振硅光子平衡接收器

IF 4.6 2区物理与天体物理 Q1 OPTICS

Optics and Laser Technology

Pub Date : 2024-11-18 DOI: 10.1016/j.optlastec.2024.112131

Jing Wang , Lin Zhu , Ben Niu , Yan Zuo , De Zhou , Rui Zhu , Hongsong Xu , Hao Wang , Wenjie Zhu , Xiong Jiang , Qifeng Liu , Dechuan Zhang

We present an improved three-channel dual-polarization silicon photonic balanced receiver specifically designed for frequency-modulated continuous-wave (FMCW) ranging systems. By leveraging silicon photonics technology, we have integrated previously discrete functional devices onto a single chip, significantly reducing system volume and enhancing integration. To address the limitations of existing multi-channel balanced receivers, we performed a systematic analysis and optimization of the receiver’s components. Our optimizations included enhancing photodetector responsivity, minimizing dark current, refining layout and wire bonding, optimizing packaging coupling processes, and improving the bandwidth and noise characteristics of the receiving link. As a result, we developed a germanium-silicon photodetector with a high responsivity of ∼ 1.09 A/W, minimal dark current of ∼ 4 nA, and bandwidth of 28 GHz. Furthermore, we realized a 3-channel dual-polarization balanced receiver chip using 130 nm CMOS technology, achieving low loss and crosstalk through layout optimization and effective packaging. The receiver was validated through an FMCW ranging system setup, demonstrating a ranging capacity exceeding 180 m across all three channels, outperforming previous works. Our receiver satisfies the potential demands of long-range and high-resolution FMCW ranging, particularly relevant for automotive LiDAR applications.

我们提出了一种改进型三通道双偏振硅光子平衡接收器，专门用于频率调制连续波（FMCW）测距系统。通过利用硅光子技术，我们将以前分立的功能器件集成到了单个芯片上，大大减少了系统体积，提高了集成度。为了解决现有多通道平衡接收器的局限性，我们对接收器的组件进行了系统分析和优化。我们的优化措施包括提高光电探测器的响应速度、最大限度地降低暗电流、改进布局和接线、优化封装耦合工艺，以及改善接收链路的带宽和噪声特性。因此，我们开发出了锗硅光电探测器，其响应率高达 1.09 A/W，暗电流最小为 4 nA，带宽为 28 GHz。此外，我们还利用 130 nm CMOS 技术实现了 3 通道双极化平衡接收器芯片，并通过布局优化和有效封装实现了低损耗和低串扰。通过 FMCW 测距系统设置对接收器进行了验证，结果表明三个通道的测距能力均超过 180 米，优于之前的研究成果。我们的接收器满足了远距离和高分辨率 FMCW 测距的潜在需求，尤其适用于汽车激光雷达应用。

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引用次数: 0

Decoupled measurement of silicon-based film and substrate thickness by hybrid reflectance spectroscopy 利用混合反射光谱法对硅基薄膜和基底厚度进行解耦测量

IF 4.6 2区物理与天体物理 Q1 OPTICS

Optics and Laser Technology

Pub Date : 2024-11-17 DOI: 10.1016/j.optlastec.2024.112143

Bai Chengpei , Sun Xinlei , Liu Zhaoran, Niu Baoxin, Wang Zizheng, Yao Chengyuan, Shen Wanfu, Hu Chunguang

Semiconductor manufacturing requires accurate measurement of film thickness, which significantly impacts the performance and reliability of device based on multilayer film structures. In this study, to simultaneously analyze multilayer films with significant thickness differences, a hybrid reflectance spectroscopy was proposed by combining differential reflectance spectroscopy (DRS) for thin films and reflectance spectroscopy (RS) for thick substrate. By integrating visible and near-infrared light, a comprehensive system is developed with microscopic imaging, DRS, and RS techniques. Furthermore, a practical algorithm was proposed to obtain the thickness differences of multilayer structure like Silicon-on-Insulator (SOI), with thickness of layers ranging from nanometers to micrometers and substrate thickness at hundreds of micrometers. The ability of wide range measurement and repeatability was verified by experiment conducted on SiO₂/Si samples, with thickness compared to nominal thickness by commercial ellipsometer across a range of 12 nm to 500 nm. The decouple of multilayer thickness was validated by experiment conducted on SOI, comparing to nominal thickness by scanning electron microscope (SEM).

半导体制造需要精确测量薄膜厚度，这对基于多层薄膜结构的设备的性能和可靠性有重大影响。为了同时分析厚度差异显著的多层薄膜，本研究提出了一种混合反射光谱法，将用于薄膜的差分反射光谱法（DRS）和用于厚基底的反射光谱法（RS）结合起来。通过整合可见光和近红外光，开发出一种集显微成像、DRS 和 RS 技术于一体的综合系统。此外，还提出了一种实用算法，用于获取多层结构（如绝缘体上硅（SOI））的厚度差异，其层厚从纳米到微米不等，而基底厚度可达数百微米。在二氧化硅/硅样品上进行的实验验证了宽范围测量的能力和重复性，商用椭偏仪在 12 纳米到 500 纳米的范围内将厚度与标称厚度进行了比较。在 SOI 上进行的实验验证了多层厚度的解耦，并通过扫描电子显微镜（SEM）与标称厚度进行了比较。

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