Optics and Lasers in Engineering最新文献_第3页

A machine-learning assisted measurement device for circadian lighting based on spectral sensors 基于光谱传感器的机器学习辅助昼夜节律照明测量装置

IF 3.5 2区工程技术 Q2 OPTICS

Optics and Lasers in Engineering

Pub Date : 2024-11-20 DOI: 10.1016/j.optlaseng.2024.108702

Jianling Huang , Cheng Zeng , Meicong Huang , Yaling Chai , Shanrong Ke , Da Xu , Lili Zheng , Xinqin Liao , Yijun Lu , Zhong Chen , Lihong Zhu , Ziquan Guo

Light has an undeniable impact on the human body, as it can to some extent affect hormone secretion and emotional changes. Spectral power distribution (SPD) is the main indicator for evaluating the quality of light sources, but traditional spectral measurement equipment is bulky and expensive, and cannot be widely used in our daily life. In order to fill this gap, this article designs a low-cost and small lighting measurement device for measuring the circadian lighting, which obtains spectral data from 8 channels in the visible light range through multi-channel spectral sensors. Machine learning methods are used to reconstruct the SPD of 81 wavelength data points, thereby improving the accuracy of designed measurement device. This device can simultaneously achieve real-time measurement of SPD and real-time monitoring of circadian related parameters, and return circadian related parameters (such as circadian action factor, melanopic efficacy of luminous radiation, equivalent melanopic lux, etc.). Results have found that the error of circadian parameters measured by this equipment is less than 5%.

光对人体的影响毋庸置疑，因为它能在一定程度上影响荷尔蒙分泌和情绪变化。光谱功率分布（SPD）是评价光源质量的主要指标，但传统的光谱测量设备体积庞大、价格昂贵，无法在日常生活中广泛使用。为了填补这一空白，本文设计了一种用于测量昼夜节律照明的低成本小型照明测量设备，通过多通道光谱传感器获取可见光范围内 8 个通道的光谱数据。利用机器学习方法重建了 81 个波长数据点的 SPD，从而提高了所设计测量设备的精度。该装置可同时实现 SPD 的实时测量和昼夜节律相关参数的实时监测，并返回昼夜节律相关参数（如昼夜节律作用因子、光辐射的黑色素效应、等效黑色素勒克斯等）。结果发现，该设备测量的昼夜节律参数误差小于 5%。

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引用次数: 0

The synchronous measurement of mechanical and magnetic characteristics of superconducting materials in extreme environments 在极端环境下同步测量超导材料的机械和磁特性

IF 3.5 2区工程技术 Q2 OPTICS

Optics and Lasers in Engineering

Pub Date : 2024-11-19 DOI: 10.1016/j.optlaseng.2024.108697

Z. Huang , X. Su , J. Deng , Y. Zhang , J. Zhou , X. Zhang

Thermomagnetic instability typically occurs before the quench of high temperature superconductors. Magnetic perturbation and thermal agitation are known to be the main driving force of thermomagnetic instability. However, the interaction between mechanical deformation and the thermomagnetic instability is still unclear. To investigate the phenomenon and inner principle of the thermomagnetic instability induced by mechanical deformation, an experimental method is proposed for the in-situ, real-time, and synchronous test of mechanical deformation and magnetic flux based on digital imaging correlation (DIC) and magneto-optical imaging (MOI). Under the current-carrying and external magnetic field conditions, uniaxial tensile tests of YBa₂Cu₃O_7-δ (YBCO) coated conductors (CCs) are carried out, in which the evolution and distribution magnetic flux induced by strain are studied. At the same time, chemical etching is adopted to explore the damage caused by mechanical deformation in YBCO layer. It is found through the experiment that the mechanical deformation can induce thermomagnetic instability, and threshold of strain for inducing flux motions is obtained. Meanwhile, magnetic flux avalanche occurs in front end of the flux penetration area in the case of current carrying. In addition, plenty of various-sizes transverse cracks are discovered in the superconducting layer whose distribution area basically coincides with the flux penetration area. The experiment results reveal the intrinsic correlation between the mechanical deformation and thermomagnetic instability of high temperature superconducting wires, which provides a direct experimental approach for the study of unpredicted quench behaviors of superconducting magnets.

热磁不稳定性通常发生在高温超导体淬火之前。众所周知，磁扰动和热搅拌是热磁不稳定性的主要驱动力。然而，机械变形与热磁不稳定性之间的相互作用仍不清楚。为了研究机械变形诱发热磁不稳定性的现象和内在原理，提出了一种基于数字成像相关（DIC）和磁光成像（MOI）的机械变形与磁通原位、实时、同步测试的实验方法。在载流和外磁场条件下，对 YBa2Cu3O7-δ (YBCO) 涂层导体（CCs）进行单轴拉伸试验，研究应变引起的磁通演化和分布。同时，还采用化学蚀刻的方法来探究 YBCO 层机械变形造成的损伤。实验发现，机械变形可诱发热磁不稳定性，并得到了诱发磁通运动的应变阈值。同时，在电流携带的情况下，磁通穿透区域的前端会出现磁通雪崩。此外，在超导层中还发现了大量不同大小的横向裂纹，其分布区域与磁通穿透区域基本重合。实验结果揭示了高温超导线材的机械变形与热磁不稳定性之间的内在联系，为研究超导磁体的未预见到的淬火行为提供了直接的实验方法。

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引用次数: 0

Dual-wavelength efficient phase imaging method based on convolutional neural networks 基于卷积神经网络的双波长高效相位成像方法

IF 3.5 2区工程技术 Q2 OPTICS

Optics and Lasers in Engineering

Pub Date : 2024-11-19 DOI: 10.1016/j.optlaseng.2024.108703

Yuanyuan Xu, Fan Yang, Gubing Cai, Yiru Fan, Wanxiang Wang

Traditional dual-wavelength interference techniques often require collecting multiple frames of intensity maps, followed by phase shifting and unwrapping to derive phase information. This method is not only time-consuming but also complex. To address these shortcomings, a high-precision and fast phase recovery method is proposed based on deep learning techniques. This approach leverages a large dataset of interferograms for training, testing based on U-Net. Remarkably, our method predicts phase information from a single frame interferogram. It significantly simplifies the computational steps and enhances a certain degree of generalization ability, as various types of fringe interferograms can be processed through separate training. Simulation tests reveal root mean square errors (RMSEs) of 0.0108 rad, 0.0232 rad, and 0.0465 rad for three different types of interferograms, indicating excellent phase recovery accuracy. Further robustness testing with Gaussian white noise shows minimal changes in RMSE, underscoring the method's stability. Real experimental results confirm the method's feasibility and better computational efficiency, achieving phase information retrieval in just 0.5 s.

传统的双波长干涉技术通常需要收集多帧强度图，然后进行相移和解包以获得相位信息。这种方法不仅耗时，而且复杂。针对这些缺点，我们提出了一种基于深度学习技术的高精度快速相位恢复方法。该方法基于 U-Net 利用大量干涉图数据集进行训练和测试。值得注意的是，我们的方法能从单帧干涉图中预测相位信息。它大大简化了计算步骤，并提高了一定程度的泛化能力，因为各种类型的干涉条纹图都可以通过单独的训练来处理。模拟测试显示，三种不同类型干涉图的均方根误差（RMSE）分别为 0.0108 rad、0.0232 rad 和 0.0465 rad，表明相位恢复精度极佳。使用高斯白噪声进行的进一步稳健性测试表明，RMSE 的变化极小，突出表明了该方法的稳定性。实际实验结果证实了该方法的可行性和更高的计算效率，只需 0.5 秒即可实现相位信息检索。

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引用次数: 0

High-quality computer-generated holography based on Vision Mamba 基于 Vision Mamba 的高质量计算机生成全息技术

IF 3.5 2区工程技术 Q2 OPTICS

Optics and Lasers in Engineering

Pub Date : 2024-11-18 DOI: 10.1016/j.optlaseng.2024.108704

Lei Yang , Shengyuan Xu , Chunzheng Yang , Chenliang Chang , Qichao Hou , Qiang Song

Deep learning, especially through model-driven unsupervised networks, offers a novel approach for efficient computer-generated hologram (CGH) generation. However, current model-driven CGH generation models are primarily built on the convolutional neural networks (CNNs), which struggle to achieve high-quality hologram reconstruction due to limited receptive fields. Although Vision Transformers (ViTs) excel at processing more distant visual information, they are burdened with huge computational load. The recent emergence of Vision Mamba (ViM) presents a promising avenue to address these challenges. In this study, we introduce the CVMNet, a lightweight model that combines the precision of convolutional layers for local feature extraction and the long-range modeling abilities of state-space models (SSMs) to enhance the quality of CGHs. By employing parallel computation for the ViM to handle feature channels, the CVMNet effectively reduces the number of model parameters. Numerical reconstruction and optical experiments demonstrate that the CVMNet can generate 1080P high-quality holograms in just 16 ms, boosting an average PSNR of over 30 dB and effectively suppressing speckle noise in reconstructed images. Additionally, the CVMNet showcases robust generalization capabilities.

深度学习，尤其是通过模型驱动的无监督网络，为高效的计算机生成全息图（CGH）提供了一种新方法。然而，目前模型驱动的全息图生成模型主要建立在卷积神经网络（CNN）基础上，由于感受野有限，很难实现高质量的全息图重建。虽然视觉变换器（ViT）在处理更远的视觉信息方面表现出色，但却要承担巨大的计算负荷。最近出现的 Vision Mamba（ViM）为解决这些难题提供了一条大有可为的途径。在本研究中，我们引入了 CVMNet，这是一种轻量级模型，它结合了卷积层用于局部特征提取的精度和状态空间模型（SSM）的远距离建模能力，从而提高了 CGH 的质量。通过采用 ViM 并行计算来处理特征通道，CVMNet 有效地减少了模型参数的数量。数值重建和光学实验证明，CVMNet 只需 16 毫秒即可生成 1080P 高质量全息图像，平均 PSNR 提高了 30 分贝以上，并有效抑制了重建图像中的斑点噪声。此外，CVMNet 还展示了强大的泛化能力。

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引用次数: 0

Multispectral polarimetric bidirectional reflectance research of plant canopy 植物冠层的多光谱偏振双向反射研究

IF 3.5 2区工程技术 Q2 OPTICS

Optics and Lasers in Engineering

Pub Date : 2024-11-18 DOI: 10.1016/j.optlaseng.2024.108688

Qingyi He , Juntong Zhan , Xuanwei Liu , Chao Dong , Dapeng Tian , Qiang Fu

Vegetation monitoring has been widely applied in various fields such as forest coverage and vegetation growth status. By measuring and analyzing the polarization of plant canopies, it is possible to infer the growth status of plants, thereby assessing their growth rate and providing effective technical means for areas such as crop yield estimation and ecological environment monitoring. To investigate the relationship between the properties of plant canopies and their polarization, a multispectral polarized light imaging system was constructed based on the BRDF (Bidirectional Reflectance Distribution Function) device. Through experiments and analysis on Christmas blue cabbage and hibiscus, the polarization characteristics of sparse and dense vegetation were detected. The results indicate that the polarization of denser vegetation canopies is significantly greater than that of sparser vegetation, with polarization degrees reaching 0.29 and 0.43 in the red waveband, exceeding the polarization in the blue and green wavebands. This advantage surpasses the influence of leaf roughness on polarization. Furthermore, a pBRDF model of plant canopies was established, and fitted images of polarization degree variation with zenith angle were obtained. Data inversion was conducted on the canopies of Christmas blue cabbage and hibiscus, resulting in root mean square errors of 2.3% and 1.1%, respectively.

植被监测已广泛应用于森林覆盖率和植被生长状况等多个领域。通过测量和分析植物冠层的偏振光，可以推断植物的生长状况，从而评估植物的生长速度，为农作物估产和生态环境监测等领域提供有效的技术手段。为了研究植物冠层特性与其偏振之间的关系，研究人员基于双向反射率分布函数（BRDF）装置构建了多光谱偏振光成像系统。通过对圣诞蓝甘蓝和木槿的实验和分析，检测了稀疏植被和茂密植被的偏振特性。结果表明，茂密植被的偏振明显大于稀疏植被，红色波段的偏振度分别达到 0.29 和 0.43，超过了蓝色和绿色波段的偏振。这一优势超过了叶片粗糙度对偏振的影响。此外，还建立了植物冠层的 pBRDF 模型，并获得了偏振度随天顶角变化的拟合图像。对圣诞蓝甘蓝和木槿的树冠进行了数据反演，结果均方根误差分别为 2.3% 和 1.1%。

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引用次数: 0

Double spiral phase filter digital in-line holography for particle field recording and tracking 用于粒子场记录和跟踪的双螺旋相位滤波器数字在线全息技术

IF 3.5 2区工程技术 Q2 OPTICS

Optics and Lasers in Engineering

Pub Date : 2024-11-16 DOI: 10.1016/j.optlaseng.2024.108694

J. Lobera , A.M. López Torres , N. Andrés , F.J. Torcal-Milla , E.M. Roche , V. Palero

The application of digital in-line holography in fluid velocimetry is mainly limited by the twin image that hinders the particle position and velocity measurements. In this work, we propose the use of two spiral phase filters in a digital in-line holography configuration to discriminate the real and virtual images. The first filter is a physical plate that modifies the object spectrum prior the recording. The second filter is a numerical frequency filter, applied in the reconstruction process, which reshape one of the particle images into a point-like image while blurs its twin image. In this way, particle tracking algorithms, based on the detection of intensity peaks, can easily locate and track particles. The good performance of double spiral phase filter in-line holography for particle field recording and particle tracking has been demonstrated experimentally in the present work.

数字在线全息技术在流体测速中的应用主要受到孪生图像的限制，孪生图像阻碍了粒子位置和速度的测量。在这项工作中，我们提出在数字在线全息配置中使用两个螺旋相位滤波器来区分真实图像和虚拟图像。第一个滤波器是一个物理板，可在记录前修改对象光谱。第二个滤波器是一个数字频率滤波器，应用于重建过程中，可将其中一个粒子图像重塑为点状图像，同时模糊其孪生图像。这样，基于强度峰值检测的粒子跟踪算法就能轻松定位和跟踪粒子。本研究通过实验证明了双螺旋相位滤波器在线全息技术在粒子场记录和粒子跟踪方面的良好性能。

引用次数: 0

Femtosecond laser processing with aberration correction based on Shack-Hartmann wavefront sensor 基于 Shack-Hartmann 波前传感器的具有像差校正功能的飞秒激光加工技术

IF 3.5 2区工程技术 Q2 OPTICS

Optics and Lasers in Engineering

Pub Date : 2024-11-16 DOI: 10.1016/j.optlaseng.2024.108693

Xiangyu Wang , Lei Zhu , Qi Zhang , Liang Yang , Min Tang , Fei Xiao , Xiaodong Wang , Shiyang Shen , Lanqiang Zhang , Youming Guo

Optical aberrations are critical for high-precision and large-depth fabrication of femtosecond lasers in transparent media. Some approaches have been demonstrated to correct these aberrations, such as calculated formulas, iterative algorithms for phase retrieval, and neural networks. However, these approaches have a few drawbacks, such as insufficient aberration correction and a lack of real-time operation, limiting the processing depth and performance of the device. Thus, this study demonstrated an aberration correction scheme with direct wavefront sensing. The aberrations during processing at different depths, from 100 to 600 μm, were measured using a Shack-Hartmann wavefront sensor. As a guide star, this sensor used the supercontinuum emitted by the plasma, which is generated by multiphoton absorption and avalanche effects in the focal region. A liquid-crystal spatial light modulator (SLM) effectively compensated the aberrations. Voxels with a constant aspect ratio of 2.82–2.91 were fabricated in different depths, significantly lower than the aspect ratio of 4.46–19.5 with uncorrected aberrations. This technology allows the precise fabrication of three-dimensional photonic devices consisting of curved waveguides at continuously different depths and improves the throughput of laser processing.

光学像差对于在透明介质中高精度、大深度制造飞秒激光器至关重要。目前已有一些方法可以校正这些像差，如计算公式、相位检索迭代算法和神经网络。然而，这些方法都有一些缺点，例如像差校正不足和缺乏实时操作，从而限制了设备的处理深度和性能。因此，本研究展示了一种直接波前传感的像差校正方案。使用 Shack-Hartmann 波前传感器测量了从 100 到 600 μm 不同深度处理过程中的像差。该传感器使用等离子体发射的超连续光作为导星，超连续光是由焦点区域的多光子吸收和雪崩效应产生的。液晶空间光调制器（SLM）有效地补偿了像差。在不同深度制造出了长宽比恒定为 2.82-2.91 的体素，明显低于未校正像差的 4.46-19.5 长宽比。这项技术可以精确制造由连续不同深度的弯曲波导组成的三维光子器件，并提高激光加工的吞吐量。

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引用次数: 0

Multifunctional processor based on cascaded switchable polarization-multiplexed metasurface 基于级联可切换偏振多路复用元表面的多功能处理器

IF 3.5 2区工程技术 Q2 OPTICS

Optics and Lasers in Engineering

Pub Date : 2024-11-16 DOI: 10.1016/j.optlaseng.2024.108691

Rui Xia, Haodong Zhu, Ruiqi Yin, Ming Zhao, Zhenyu Yang

In many optical applications, vortex beam is widely used in optical communications, quantum information processing and other fields due to its unique properties. And in the field of imaging, it is crucial to obtain high quality and clear images. Current strategies mainly observe the interference fringes of the vortex beam and the Gaussian beam or use external optics to measure the topological charges (TCs), and apply machine learning in the back-end processing to denoise the image. The emerging diffractive deep neural network (D²NN) proposes a novel solution. Here, we introduce a multifunctional processor based on cascaded switchable polarization-multiplexed metasurface. It realizes the TC measurement and image denoising by exploiting the polarization-sensitive properties of anisotropic meta-atoms, which generate different phase responses under varying polarization states of incident light. Different types of noisy images, noise models, and noise ratios can be denoised by switching the metasurface. This study highlights the potential applications of integrating metasurfaces with D²NN through numerical simulation validation, expanding possibilities by transforming metasurfaces into multifunctional processors.

在许多光学应用中，涡旋光束因其独特的特性被广泛应用于光通信、量子信息处理等领域。而在成像领域，获得高质量的清晰图像至关重要。目前的策略主要是观测涡旋光束与高斯光束的干涉条纹，或利用外部光学器件测量拓扑电荷（TC），并在后端处理中应用机器学习对图像进行去噪。新兴的衍射深度神经网络（D2NN）提出了一种新的解决方案。在此，我们介绍一种基于级联可切换偏振多路复用元表面的多功能处理器。它利用各向异性元原子的偏振敏感特性，在入射光的偏振态变化时产生不同的相位响应，从而实现偏振测量和图像去噪。通过切换元面，可以对不同类型的噪声图像、噪声模型和噪声比进行去噪。这项研究通过数值模拟验证，强调了元表面与 D2NN 集成的潜在应用，通过将元表面转化为多功能处理器，拓展了应用的可能性。

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引用次数: 0

Efficient point cloud occlusion method for ultra wide-angle computer-generated holograms 超广角计算机生成全息图的高效点云遮挡法

IF 3.5 2区工程技术 Q2 OPTICS

Optics and Lasers in Engineering

Pub Date : 2024-11-15 DOI: 10.1016/j.optlaseng.2024.108678

Juan Martinez-Carranza , Jose Martinez-Carranza , Tomasz Kozacki

Holographic Near Eye Displays (HNEDs) are meant to be the next generation of electronic devices that enable projecting three-dimensional images directly to the eyes. This is possible because computer-generated holograms (CGHs), the backbone of HNEDs, encode accurate wavefront information from virtual objects. An immersive experience requires that these CGHs can reproduce large and highly detailed objects. Moreover, an occlusion culling algorithm is necessary to remove back surfaces that do not contribute to the scene, which provides a better sense of reality. Although there is a vast family of occlusion culling methods, none of these, to the best of our knowledge, consider occlusion when calculating CGHs for field of views (FoV) larger than 90° This work proposes a point cloud occlusion culling method for CGHs that projects images with angles larger than 90° Our approach is based on the geometry of the non-pupil Near Eye Display configuration. It is shown that this configuration provides the proper geometrical conditions that can be used for setting fast occlusion culling of unwanted back points. Occlusion culling with our method is carried out with clouds larger than 7-million-point sources and CGHs resolution of 4 K and 8K. It is demonstrated that our method is at least 5 times faster than current solutions. Furthermore, occluded clouds are used for calculating CGHs that are numerically and optically reconstructed. The obtained results confirm that our method provides high-quality occluded clouds, enabling high-quality production of CGHs with large FoV.

全息近眼显示器（HNED）是下一代电子设备，可直接向眼睛投射三维图像。之所以能做到这一点，是因为全息近眼显示器的核心部件--计算机生成的全息图（CGH）能从虚拟物体中获取准确的波前信息。要获得身临其境的体验，这些全息图必须能够再现大型和高度精细的物体。此外，还需要一种遮挡剔除算法，以去除对场景无益的背面，从而提供更好的真实感。虽然有大量的遮挡剔除方法，但据我们所知，没有一种方法在计算视场角（FoV）大于 90° 的 CGH 时考虑到遮挡。研究表明，这种配置提供了适当的几何条件，可用于设置快速遮挡剔除不需要的背景点。使用我们的方法进行遮挡剔除时，云的点数大于 700 万，CGH 的分辨率为 4 K 和 8K。结果表明，我们的方法比目前的解决方案至少快 5 倍。此外，在计算数值和光学重建的 CGHs 时还使用了遮挡云。所得结果证实，我们的方法可以提供高质量的遮挡云，从而高质量地生成大视场角的 CGH。

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引用次数: 0

In-situ full-wafer metrology via coupled white light and monochromatic stroboscopic illumination 通过耦合白光和单色频闪照明进行原位全晶片测量

IF 3.5 2区工程技术 Q2 OPTICS

Optics and Lasers in Engineering

Pub Date : 2024-11-15 DOI: 10.1016/j.optlaseng.2024.108692

Jack B.P. Atkinson, Jonathan R. Howse

This work presents a novel optical setup to provide scalable in-situ metrology during spin coating. Stroboscopic white light imaging provides high resolution color videos of the process, at a temporal resolution matching the spin speed, where thin film interference colors are observed. Monochromatic specular reflection intensity data from the center of rotation provides a thickness profile at this point. By developing a color to thickness relationship in-situ with the combination of these techniques and leveraging the large-area data provided by color imaging, the thickness at any point on the wafer is reconstructed via a mapping procedure with minimal a-priori information. Experiments are carried out on full 3″ diameter wafers spun with pure xylene or pure butyl acetate, and the thickness profile at all points on the wafer can be determined. Differences in the topology of these solvents whilst drying are linked back to the solvent properties. The color to thickness mapping procedure is shown to have less than 5 % error in determined thickness values between 2μm and 100nm. The possible length scale resolved by the imaging is fully discussed as a function of radius, spin speed, strobe pulse duration and hardware used. The studies in this work achieved a minimum lateral resolution of 315μm when observing a full wafer, which is sufficiently detailed to properly reconstruct thickness variations caused by common spin-coating defects such as comets. The large area and scalable nature of this metrology technique lends itself to applications in semiconductor manufacturing where substrates of 300 mm are standard.

这项工作展示了一种新型光学装置，可在旋转镀膜过程中提供可扩展的原位计量。频闪白光成像技术可提供高分辨率的过程彩色视频，其时间分辨率与旋转速度相匹配，在此可观察到薄膜干涉色。来自旋转中心的单色镜面反射强度数据可提供该点的厚度轮廓。通过结合这些技术和利用彩色成像提供的大面积数据，在原位建立起颜色与厚度的关系，从而以最少的先验信息通过映射程序重建晶片上任何一点的厚度。在使用纯二甲苯或纯醋酸丁酯纺丝的直径为 3 英寸的完整晶片上进行实验，可以确定晶片上所有点的厚度轮廓。这些溶剂在干燥过程中的拓扑结构差异与溶剂特性有关。从颜色到厚度的映射程序显示，在 2 微米到 100 纳米之间，确定的厚度值误差小于 5%。成像分辨的可能长度范围作为半径、旋转速度、频闪脉冲持续时间和所用硬件的函数进行了充分讨论。这项工作中的研究在观测整个晶片时实现了最小 315 微米的横向分辨率，其细节足以正确重建由常见旋涂缺陷（如彗星）引起的厚度变化。这种计量技术的大面积和可扩展性使其适合应用于半导体制造领域，在这些领域中，300 毫米的基片是标准基片。

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引用次数: 0