相干拉曼散射（CRS）技术作为一种重要的无标记化学成像技术，通过相干激发分子协同振动对拉曼散射信号进行增益，显著地提高了成像速度，广泛应用于材料学、生物化学、肿瘤诊断、药代动力学等领域。超快脉冲激光器的出现实现了亚皮秒持续时间的脉冲输出，使得通过脉冲激发实现大量振动模式的同步相干激发成为新的CRS实现途径。从相干拉曼散射基本原理出发，介绍时域相干拉曼散射的主要实现途径，着重讨论时域受激拉曼散射（SRS）和时域相干反斯托克斯拉曼散射（CARS）的最新进展与应用。

拉曼显微成像技术无需样本制备，具有无损、无创、对水溶液不敏感的优点，可在微米或纳米尺度下表征样本的生化组分及分布，成为生命科学领域重要的研究工具。随着对复杂生物样本研究的不断深入，拉曼显微成像也被期待能够实现对生物样本中的分子组成与分布的动态立体观测。首先，系统性地梳理近年来三维拉曼显微成像技术的研究进展，包括基于自发拉曼散射、相干拉曼散射、表面增强拉曼散射以及拉曼标签的不同三维成像方法的技术手段、改进策略与实验结果。然后，总结了不同成像技术在细胞生物学、发育生物学等方面的应用进展。最后展望了不同三维拉曼显微成像技术在生物医学光学显微成像技术应用中所面临的挑战和发展前景。

Cancer cells dysregulate lipid metabolism to accelerate energy production and biomolecule synthesis for rapid growth. Lipid metabolism is highly dynamic and intrinsically heterogeneous at the single cell level. Although fluorescence microscopy has been commonly used for cancer research, bulky fluorescent probes can hardly label small lipid molecules without perturbing their biological activities. Such a challenge can be overcome by coherent Raman scattering (CRS) microscopy, which is capable of chemically selective, highly sensitive, submicron resolution and high-speed imaging of lipid molecules in single live cells without any labeling. Recently developed hyperspectral and multiplex CRS microscopy enables quantitative mapping of various lipid metabolites in situ. Further incorporation of CRS microscopy with Raman tags greatly increases molecular selectivity based on the distinct Raman peaks well separated from the endogenous cellular background. Owing to these unique advantages, CRS microscopy sheds new insights into the role of lipid metabolism in cancer development and progression. This review focuses on the latest applications of CRS microscopy in the study of lipid metabolism in cancer.

Benefiting from the developments of advanced optical microscopy techniques, the mysteries of biological functions at the cellular and subcellular levels have been continuously revealed. Stimulated Raman scattering (SRS) microscopy is a rapidly growing technique that has attracted broad attentions and become a powerful tool for biology and biomedicine, largely thanks to its chemical specificity, high sensitivity and fast image speed. This review paper introduces the principles of SRS, discusses the technical developments and implementations of SRS microscopy, then highlights and summarizes its applications on biological cellular machinery and finally shares our visions of potential breakthroughs in the future.Benefiting from the developments of advanced optical microscopy techniques, the mysteries of biological functions at the cellular and subcellular levels have been continuously revealed. Stimulated Raman scattering (SRS) microscopy is a rapidly growing technique that has attracted broad attentions and become a powerful tool for biology and biomedicine, largely thanks to its chemical specificity, high sensitivity and fast image speed. This review paper introduces the principles of SRS, discusses the technical developments and implementations of SRS microscopy, then highlights and summarizes its applications on biological cellular machinery and finally shares our visions of potential breakthroughs in the future.

随着光学显微技术的发展，人们得以在亚微米级的尺度观察微观世界，对破译生命活动密码起到了关键性推动作用。其中，相干拉曼散射（CRS）显微术作为一类基于分子特定振动提供成像衬度的技术，通过非线性光学过程大大增强了拉曼散射的信号，提高了成像速率和检测的灵敏度。根据非线性光学过程的不同，可将相干拉曼散射分为相干反斯托克斯拉曼散射（CARS）和受激拉曼散射（SRS）。相较于CARS，SRS具有无非共振背景干扰、定量分析等优点，使之备受关注。将介绍相干拉曼散射的基本原理，并着重介绍受激拉曼散射的发展与应用。

相干拉曼散射显微技术作为一种新型的成像技术,具有无标记、高特异性、非侵入等优点,已被广泛用于化学结构及物质成分分析。近年来,光子学、生物医学和显微成像技术等领域的相互交叉和融合发展,极大地推动了相干拉曼散射显微成像技术在生物医学领域的应用。简要介绍了相干拉曼散射显微成像的基本原理、分类、系统构成,同时概述了相干拉曼散射显微成像技术近年来在生物医学领域的应用,包括检测、脂类分析和蛋白质构象变化等,最后对其未来发展进行了展望。

相干拉曼散射具有非侵入、无标记、化学特异性的优点,广泛用于生物组织成像、药代动力学等领域。主要介绍了光纤式相干拉曼散射(CRS)成像光源的实现方式及特点,总结了超连续谱展宽、孤子自频移和四波混频技术在提高双色超短脉冲输出功率、调谐范围、光谱分辨率方面的新进展。报道了基于四波混频的光参量振荡技术在产生可调谐双色超短脉冲方面的最新进展,采用全保偏光纤光路和光子晶体光纤,结合色散滤波和偏振操控技术,获得时间自同步、空间自重合、波长可调谐的双色超短脉冲,可实现脂类、蛋白和核酸的非侵入、无标记光谱检测与成像,为实现结构紧凑、使用方便、环境稳定的CRS提供了一个有效的技术途径。

Synchronized time-lens source is a novel method to generate synchronized optical pulses to modelocked lasers, and has found widespread applications in coherent Raman scattering microscopy. Relative timing jitter between the mode-locked laser and the synchronized time-lens source is a key parameter for evaluating the synchronization performance of such synchronized laser systems. However, the origins of the relative timing jitter in such systems are not fully determined, which in turn prevents the experimental efforts to optimize the synchronization performance. Here, we demonstrate, through theoretical modeling and numerical simulation, that the photodetection could be one physical origin of the relative timing jitter. Comparison with relative timing jitter due to the intrinsic timing jitter of the mode-locked laser is also demonstrated, revealing different qualitative and quantitative behaviors. Based on the nature of this photodetection-induced timing jitter, we further propose several strategies to reduce the relative timing jitter. Our theoretical results will provide guidelines for optimizing synchronization performance in experiments.