张静 1,2温俊鹏 1,2朱喆 1,2韦小明 1,2,3,4,*杨中民 1,2,3,4,5
1 华南理工大学物理与光电学院,广东 广州 510640
2 华南理工大学发光材料与器件国家重点实验室,广东 广州 510640
3 华南理工大学广东省特种光纤材料与器件工程技术研究开发中心,广东 广州 510640
4 华南理工大学广东省光纤激光材料及应用技术重点实验室,广东 广州 510640
5 华南师范大学未来技术研究院,广东 广州 510006
双光子激发显微镜是研究脑神经元活动的重要工具。基于传统机械式逐点激光扫描技术的双光子激发显微镜成像速度较慢,无法进行脑神经元活动的实时观察研究。此外,高速双光子激发显微成像需要配置高重复频率飞秒激光,以保证在较短的像素停留时间内获得较高的信息强度。本文提出了基于声光偏转的并行GHz超快激光扫描技术,通过设计射频编码方案,在920 nm波段搭建了高速GHz超快激光扫描系统。通过调整时间和空间重合,最终在15~31 MHz频率范围内获得了33个可分辨的并行GHz超快激光扫描光束,为实现高速双光子激发显微成像提供了技术支撑。
双光子显微成像 声光偏转 高速激光扫描 飞秒激光 光学学报
2023, 43(23): 2318001
Author Affiliations
Abstract
1 Britton Chance Center and MoE Key Laboratory for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, P. R. China
2 MoE Key Laboratory for Biomedical Photonics, Collaborative Innovation Center for Biomedical Engineering, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430074, P. R. China
3 Research Unit of Multimodal Cross Scale, Neural Signal Detection and Imaging, Chinese Academy of Medical Sciences, HUST-Suzhou Institute for Brainsmatics, JITRI Suzhou, P. R. China
The volumetric imaging of two-photon microscopy expands the focal depth and improves the throughput, which has unparalleled superiority for three-dimension samples, especially in neuroscience. However, emerging in volumetric imaging is still largely customized, which limits the integration with commercial two-photon systems. Here, we analyzed the key parameters that modulate the focal depth and lateral resolution of polarized annular imaging and proposed a volumetric imaging module that can be directly integrated into commercial two-photon systems using conventional optical elements. This design incorporates the beam diameter adjustment settings of commercial two-photon systems, allowing flexibility to adjust the depth of focus while maintaining the same lateral resolution. Further, the depth range and lateral resolution of the design were verified, and the imaging throughput was demonstrated by an increase in the number of imaging neurons in the awake mouse cerebral cortex.
Volumetric imaging Bessel beam two-photon microscopy Journal of Innovative Optical Health Sciences
2023, 16(4): 2350017
1 曲阜师范大学网络空间安全学院,山东 济宁 273100
2 中国科学院深圳先进技术研究院生物医学光学与分子影像研究中心,广东 深圳 518055
3 香港理工大学生物医学工程系,香港 999077
4 香港理工大学深圳研究院,广东 深圳 518055
双光子成像技术已被广泛应用于活体肿瘤成像、神经功能成像以及大脑疾病研究等领域,但双光子成像视场较小(视场直径一般在1 mm以内),限制了其进一步应用。虽然通过特殊的光学设计或者自适应光学技术能够有效增大视场,但复杂的光路设计、高昂的器件成本以及繁琐的操作过程限制了这些技术的推广。提出了一种利用深度学习技术替代自适应光学技术扩展双光子成像视场的新思路,在低成本(无须特殊物镜,无须相位补偿装置)、易操作的前提下实现了大视场双光子成像。设计了一种适用于光学显微系统中扩展双光子成像视场的nBRAnet网络框架,为使该网络框架可以更好地利用特征图信息,在该框架中引入残差模块和空间注意力机制,同时去除了数据归一化处理,以增加图像对比度信息。实验结果表明:所提深度学习方法可以有效地代替自适应光学技术,增强扩展视场中的精细结构特征,并恢复扩展视场的成像分辨率和信噪比,使双光子成像视场直径扩展到3.46 mm,峰值信噪比超过27 dB。深度学习方法具有成本低、操作简单、图像增强效果显著等特点,有望为跨区域脑成像或全脑成像提供一种经济实用的方案。
显微 深度学习 自适应光学 大视场 双光子成像
1 广西大学 物理科学与工程技术学院和脑与智能研究中心, 广西 南宁 530004
2 中国科学院 苏州生物医学工程技术研究所, 江苏 苏州 215163
双光子显微镜在厚生物组织中依然可以保持良好的空间分辨率,这一优点使得其诞生不久就被应用于在体脑成像研究。而神经网络在时空多个维度均具有跨尺度的特点,为满足脑科学研究中在体跨尺度脑成像的需求,双光子显微镜近年来有了快速且显著的发展。本文首先介绍了双光子显微镜的工作原理,然后在成像视野、成像通量、成像深度、分辨率、微型化5个方面详细综述了双光子显微镜研究的新进展,并深入分析了跨尺度双光子在体显微成像技术的难点及未来挑战。
在体脑成像 跨尺度 双光子显微镜 in-vivo brain imaging cross-scale two-photon microscopy
红外与激光工程
2022, 51(11): 20220550
超分辨显微成像技术是生物医学领域的重要成像工具,它通过突破光学衍射的极限,以纳米级尺度解析大脑神经元的结构,其在活体大脑成像中的应用对于神经科学的发展具有重要影响。由于组织光散射、生物相容性、成像系统兼容性等因素,超分辨显微成像技术在活体大脑成像的深度、速度、时间等方面都受到限制。基于传统的双光子显微成像策略,本文介绍了目前应用于活体大脑成像的受激发射损耗显微成像和结构光照明显微成像的研究进展,分析了它们存在的困难和挑战,最后总结了应对挑战的思路并对未来的发展进行了展望。
医用光学 超分辨显微成像 活体成像 大脑成像 双光子显微成像 受激发射损耗显微成像 结构光照明显微成像 中国激光
2022, 49(20): 2007301
Author Affiliations
Abstract
1 State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084, China
2 IDG/McGovern Institute for Brain Research, Tsinghua University, Beijing 100084, China
Localized wavefront aberrations would introduce artifacts in biomedical imaging, which, however, are often neglected, as their compensations are at the cost of the field-of-view. Here, we show rarely reported local artifacts in two-photon imaging of dendrites beneath blood vessels in a mouse brain in vivo and interpret the phenomena via numerical simulations. The artifacts of divided parallel structures are found to be induced by coma and astigmatism, resulting from sample tilting and the cylinder shape of vasculatures, respectively. Different from that in single-photon microscopy, such artifacts in nonlinear microscopy show unique characteristics and should be recognized for proper interpretation of the images.
biomedical imaging two-photon microscopy wavefront aberration artifacts of dendrites mouse cortex Chinese Optics Letters
2021, 19(12): 121701
1 贵州大学 a.物理学院
2 b.贵州省光电子技术与应用重点实验室, 贵阳 550025
3 中国科学院深圳先进技术研究院生物医学光学与分子影像研究室, 深圳 518055
本文提出利用离轴抛物镜共焦中继系统来改善双光子成像视场边缘像质变差的问题, 进而提升双光子成像视场。不同于传统的双胶合透镜扫描中继系统, 离轴抛物镜共焦扫描中继系统由一对离轴抛物镜构成, 扫描振镜位于抛物面镜焦点处。仿真和试验结果均显示, 该系统能有效优化视场边缘的像散、场曲和畸变情况, 提高成像质量。利用该扫描系统, 我们实现了视场为2.4 mm×2.4 mm, 横向分辨率为1 μm的大视场双光子显微成像, 能清晰分辨小鼠大脑切片中的神经轴突结构。
离轴抛物面反射镜 双光子成像 共焦扫描中继 像差 大视场 off-axis parabolic mirror two-photon microscopy afocal scanning relay aberration large field-of-view
Author Affiliations
Abstract
1 State Key Laboratory of Modern Optical Instrumentation, Department of Neurobiology of the First A±liated Hospital, Zhejiang University School of Medicine, Hangzhou 310027, P. R. China
2 College of Optical Science and Engineering, Zhejiang University, Hangzhou 310027, P. R. China
3 NHC and CAMS Key Laboratory of Medical Neurobiology, Department of Neurobiology, Center for Neuroscience, Zhejiang University School of Medicine, Hangzhou 310058, P. R. China
Two-photon microscopy normally suffers from the scattering of the tissue in biological imaging. Multidither coherent optical adaptive technique (COAT) can correct the scattered wavefront in parallel. However, the determination of the corrective phases may not be completely accurate using conventional method, which undermines the performance of this technique. In this paper, we theoretically demonstrate a method that can obtain more accurate corrective phases by determining the phase values from the square root of the fluorescence signal. A numerical simulation model is established to study the performance of adaptive optics in two-photon microscopy by combining scalar diffraction theory with vector diffraction theory. The results show that the distortion of the wavefront can be corrected more thoroughly with our method in two-photon imaging. In our simulation, with the scattering from a 450-μm-thick mouse brain tissue, excitation focal spots with higher peak-to-background ratio (PBR) and images with higher contrast can be obtained. Hence, further enhancement of the multidither COAT correction performance in two-photon imaging can be expected.
Coherent optical adaptive technique two-photon microscopy adaptive optics deep tissue Journal of Innovative Optical Health Sciences
2019, 12(4): 1942003