1 浙江大学光电科学与工程学院，浙江 杭州 310027
2 浙江大学嘉兴研究院智能光电创新中心，浙江 嘉兴 324000
在光学相干层析血流造影（OCTA）系统的实际应用中，高质量数据的采集受到多种因素的干扰，如屈光调节、扫描区域移动、动态成像过程中受试对象眼睛状态波动等。笔者构建了一种基于图像处理单元（GPU）的OCTA数据实时处理框架，使用C++和CUDA开发系统软件，实现了逆信噪比-复值退相关光学相干层析血流造影（ID-OCTA）的实时信号处理与图像显示，线处理速度达到了365 kHz。同时，通过闪烁光刺激诱发小鼠视网膜功能性充血实验，证明了本研究实现的OCTA投影图像实时显示功能有助于操作人员调节系统，监测受试对象的状态，从而提高数据采集成功率。
生物医学成像 光学相干层析血流造影 实时成像 功能性充血
在激光粉末床熔融（LPBF）成形过程中，铺粉异常导致的沉积缺陷会严重影响成形零件的表面及内部质量，但目前缺乏针对性的在线监测与诊断方案。采用光电探测器和高速相机在线监测成形过程中的光强和熔池面积信号，探究不同粉末厚度条件下熔池尺度光信号的变化规律，实现对零件质量的初步诊断。研究结果表明，粉末厚度的异常增加会导致零件熔化状态出现波动，并最终导致严重的球化。表面粗糙度从正常打印状态的5 μm显著增加至100 μm以上，同时在零件内部形成了未熔合孔隙缺陷。阐述了粉末厚度对沉积缺陷的影响机制，深入分析了光强与熔池面积的特征及其相互关系，提出了一种基于阈值百分比诊断沉积缺陷的信号监测方法。
增材制造 激光粉末床熔融 在线监测 熔池光信号 沉积缺陷 中国激光
2024, 51(10): 1002308
香港大学物理系新基石科学实验室，香港 999077
耦合等离激元体系在光场调控、光学传感、光学成像及光电器件等领域中有着广泛应用。目前，阻碍耦合等离激元进一步实用化发展的关键问题是金属材料具有较大的损耗。结合数值仿真方法，从理论上研究了耦合等离激元的损耗机理，并进一步分析复频率光源激励对耦合等离激元体系的作用，提出了通过合成复频率波的方法来补偿损耗，从而恢复被削弱的耦合共振信号。所提优化手段具有泛用性高且无需额外成本的优势，研究结果对耦合等离激元体系在各个领域中的研究发展具有借鉴意义，有利于挖掘该体系的潜在应用价值。
物理光学 纳米光学 等离激元 复频率波 光学传感 光学学报
2024, 44(10): 1026019
1 苏州大学物理科学与技术学院，江苏 苏州 215006
2 山东师范大学物理与电子科学学院，山东 济南 250358
回顾了光场相干与偏振联合调控的研究进展，重点介绍了具有特殊空间相干结构的二维部分相干矢量光束的表征、合成及在复杂环境中的鲁棒传输特性；结合纳米光子学的发展，将二维部分相干矢量光束推广到了三维部分相干矢量光场，给出了三维部分相干矢量光场的相干与偏振表征，分析了部分相干紧聚焦矢量光场中的三维偏振结构，包括偏振维度、三维非寻常偏振态、自旋角动量结构等。研究表明相干性在赋予了矢量结构光场新颖自由度的同时，导致了二维矢量光束的鲁棒传输特性以及紧聚焦矢量光场新型三维偏振结构。
部分相干光场 矢量光场 光场调控 相干与偏振 光场相干结构调控 光学学报
2024, 44(10): 1026007
1 深圳大学射频异质异构集成全国重点实验室，微纳光电子学研究院纳米光子学研究中心，广东 深圳 518060
2 之江实验室智能感知研究院，浙江 杭州 311100
自旋角动量是基本粒子和场的一个基本的动力学物理量，它在光与物质相互作用中扮演着极其重要的角色。在光学研究中，光的自旋角动量与圆极化密切相关，通过研究光学自旋与物质或结构的相互作用产生了许多新颖有趣的光学现象和光学应用，并诞生了自旋光学这一新兴学科。过去的研究中，研究人员主要聚焦在与平均波矢方向平行的纵向光学自旋。近年来，科研人员通过研究限制场如聚焦波、导波和倏逝波等的自旋轨道耦合性质，发现了一类新型的光学自旋，这类自旋与平均波矢方向垂直，因此被称为光学横向自旋。横向自旋具有自旋动量绑定的性质，一经发现便受到研究人员的广泛关注。横向自旋的发现拓展了光学自旋轨道相互作用的内容，并在光学操纵、光学精密检测、手性量子光学和光学自旋拓扑态等领域具有广阔的应用前景。本文从理论、实验技术和应用3个方面详细介绍自旋光学的最新进展。自旋光学的理论概念和框架可为研究人员进一步开拓基于光学自旋在光学成像、光学探测、光通信和量子技术等领域的应用发挥巨大的作用，同时也可拓展到一般经典波场，比如流体波、声波和引力波等。
物理光学 自旋角动量 自旋动量绑定 自旋轨道耦合 光学微分计算 光学探测 横向光学力 光学学报
2024, 44(10): 1026002
1 自适应光学全国重点实验室，四川 成都 610209
2 中国科学院光电技术研究所，四川 成都 610209
3 中国科学院大学，北京 100049
4 山东高等技术研究院，山东 济南 250100
Overview: Gravitational waves are spacetime oscillations radiated outward by accelerating mass objects. Significant astronomical events in the universe, such as the merging of massive black holes, emit stronger gravitational waves. Detecting gravitational waves allows for a deeper study of the laws governing celestial bodies and the origins of the universe, making accurate detection crucial. Gravitational wave detection technology utilizes Michelson interferometers to convert the extremely faint spacetime fluctuations caused by gravitational waves into measurable changes in optical path length. Recently, ground-based large Michelson interferometers have achieved direct detection of high-frequency gravitational waves. However, the detection of low-frequency gravitational waves, which is equally important, is not feasible on the ground due to arm length and ground noise issues. This necessitates the construction of ultra-large Michelson interferometers in space for low-frequency gravitational wave detection. Spaceborne gravitational wave detection telescopes play a vital role in collimating bidirectional beams in ultra-long interferometric optical paths in space. The extremely subtle changes in optical path caused by gravitational waves impose high demands for pm-level optical path length stability and below 10?10 level backscattered light in these telescopes. The ultra-high level index requirements exceed the precision limits of current ground testing techniques for telescopes. To ensure that spaceborne telescopes maintain their ultra-high design performance in the orbital environment, developing testing and evaluation techniques for these key indicators is a crucial prerequisite for the success of the space gravitational wave detection program. This paper provides an overview of the development of spaceborne gravitational wave detection telescopes, both domestically and internationally. It focuses on the current status and some test results of optical path length stability and backscattered light testing of telescopes under development, as well as further testing plans, providing a reference for the testing and evaluation of Chinese space gravitational wave detection space-borne telescopes.
空间引力波探测 星载望远镜 地面测试 光程稳定性 后向杂散光 space gravitational wave detection spaceborne telescope ground test optical path length stability backscattered light
Author Affiliations
Abstract
1 State Key Laboratory of Low-dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing, China
2 Frontier Science Center for Quantum Information, Beijing, China
3 Jinsp Company Limited, Beijing, China
4 Beijing Institute of Technology, Beijing, China
5 Institute of Forensic Science, Ministry of Public Security Beijing, China
6 Department of Neurosurgery, Beijing Tsinghua Changgung Hospital, School of Clinical Medicine and Institute of Precision Medicine, Tsinghua University, Beijing, China
In this paper, we present a distal-scanning common path probe for optical coherence tomography (OCT) equipped with a hollow ultrasonic motor and a simple and specially designed beam-splitter. This novel probe proves to be able to effectively circumvent polarization and dispersion mismatch caused by fiber motion and is more robust to a variety of interfering factors during the imaging process, experimentally compared to a conventional noncommon path probe. Furthermore, our design counteracts the attenuation of backscattering with depth and the fall-off of the signal, resulting in a more balanced signal range and greater imaging depth. Spectral-domain OCT imaging of phantom and biological tissue is also demonstrated with a sensitivity of dB and a lateral resolution of m. This low-cost probe offers simplified system configuration and excellent robustness, and is therefore particularly suitable for clinical diagnosis as one-off medical apparatus.
Common path optical coherence tomography endoscopic probe Journal of Innovative Optical Health Sciences
2024, 17(3): 2350034
Author Affiliations
Abstract
1 School of Computer Science and Engineering, Xi’an University of Technology, Xi’an, China
2 School of Information Science and Technology, Northwest University, Xi’an 710127, China
Optical molecular tomography (OMT) is a potential pre-clinical molecular imaging technique with applications in a variety of biomedical areas, which can provide non-invasive quantitative three-dimensional (3D) information regarding tumor distribution in living animals. The construction of optical transmission models and the application of reconstruction algorithms in traditional model-based reconstruction processes have affected the reconstruction results, resulting in problems such as low accuracy, poor robustness, and long-time consumption. Here, a gates joint locally connected network (GLCN) method is proposed by establishing the mapping relationship between the inside source distribution and the photon density on surface directly, thus avoiding the extra time consumption caused by iteration and the reconstruction errors caused by model inaccuracy. Moreover, gates module was composed of the concatenation and multiplication operators of three different gates. It was embedded into the network aiming at remembering input surface photon density over a period and allowing the network to capture neurons connected to the true source selectively by controlling three different gates. To evaluate the performance of the proposed method, numerical simulations were conducted, whose results demonstrated good performance in terms of reconstruction positioning accuracy and robustness.
Optical molecular tomography gates module positioning accuracy robustness Journal of Innovative Optical Health Sciences
2024, 17(3): 2350027
Author Affiliations
Abstract
1 Institute of Modern Optics, Nankai University, Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, Tianjin 300350, China
2 Department of Thyroid and Neck Tumor, Tianjin Medical University Cancer Institute and Hospital National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China
Limited by the dynamic range of the detector, saturation artifacts usually occur in optical coherence tomography (OCT) imaging for high scattering media. The available methods are difficult to remove saturation artifacts and restore texture completely in OCT images. We proposed a deep learning-based inpainting method of saturation artifacts in this paper. The generation mechanism of saturation artifacts was analyzed, and experimental and simulated datasets were built based on the mechanism. Enhanced super-resolution generative adversarial networks were trained by the clear–saturated phantom image pairs. The perfect reconstructed results of experimental zebrafish and thyroid OCT images proved its feasibility, strong generalization, and robustness.
Optical coherence tomography saturation artifacts deep learning image inpainting Journal of Innovative Optical Health Sciences
2024, 17(3): 2350026
Author Affiliations
Abstract
1 State Key Laboratory of Dynamic Measurement Technology, North University of China, Taiyuan 030051, China
2 School of Information & Communication Engineering, North University of China, Taiyuan 030051, China
3 School of Instrument & Electronics, North University of China, Taiyuan 030051, China
Sensors based on optical resonators often have their measurement range limited by their cavity linewidth, particularly in the measurement of time-varying signals. This paper introduces a method for optical frequency shift detection using multiple harmonics to expand the dynamic range of sensors based on optical resonators. The proposed method expands the measurement range of optical frequency shift beyond the cavity linewidth while maintaining measurement accuracy. The theoretical derivation of this method is carried out based on the equation of motion for an optical resonator and the recursive relationship of the Bessel function. Experimental results show that the dynamic range is expanded to 4 times greater than the conventional first harmonic method while still maintaining accuracy. Furthermore, we present an objective analysis of the correlation between the expansion factor of the method and the linewidth and free spectrum of the optical resonator.
optical resonator optical frequency shift multiple harmonics dynamic range expansion Chinese Optics Letters
2024, 22(4): 041201
