发表机构
Aix Marseille University, CNRS, Centrale Med, Institut Fresnel; Institut Universitaire de France (IUF); Morgridge Institute for Research; XLIM, CNRS UMR 7252, Université de Limoges（艾克斯-马赛大学、法国国家科学研究中心、中央理工-马赛学院、菲涅耳研究所; 法兰西学院; 莫格里奇研究所; XLIM实验室、法国国家科学研究中心UMR 7252、利摩日大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文提出一种结合高功率OPA、散斑照明和QLSI的相位分辨宽场高光谱CARS显微镜，抑制非共振背景，实现大视场快速成像，并用于微塑料和肝脏脂肪变性成像。
AI 中文摘要
相干反斯托克斯拉曼散射（CARS）显微镜能够对生物样品和材料进行无标记化学成像。传统上，CARS采用点扫描方式实现，每次探测单一振动模式。高光谱CARS通过依次探测多个拉曼模式来增强化学特异性。然而，测量得到的CARS强度会受到非共振背景的畸变影响，该背景会加宽并移动拉曼峰，从而妨碍高光谱图像的可解释性。在此，我们提出一种相位敏感、宽场高光谱CARS显微镜方案，用于抑制非共振背景。该方法结合了三个关键组件：高功率皮秒可调谐光参量放大器（OPA）、散斑照明以及基于四波横向剪切干涉法（QLSI）的定量相位成像。高功率OPA提供高效非线性激发所需的峰值功率。散斑照明将光能分布到物镜后瞳上，并减轻相干成像伪影。QLSI能够同时测量CARS场的振幅和相位，从而无需外部参考光束即可分离共振和非共振贡献。这一独特组合使得在超过60×60微米平方的视场上，以1.4 Hz的帧率实现实用的相位分辨CARS成像。我们通过获取微塑料和肝脏脂肪变性在整个CH伸缩区域的图像来展示该方法。
英文摘要
Coherent anti-Stokes Raman scattering (CARS) microscopy enables label-free chemical imaging of biological samples and materials. Conventionally, CARS is implemented using a point-scanning approach that probes a single vibrational mode at a time. Hyperspectral CARS enhances chemical specificity by sequentially addressing multiple Raman modes. However, the measured CARS intensity is distorted by an undesired non-resonant background, which broadens and shifts the Raman peaks, thereby hindering the interpretability of hyperspectral images. Here, we introduce a phase-sensitive, wide-field hyperspectral CARS microscopy scheme that suppresses the non-resonant background. The proposed approach combines three key components: a high-power picosecond tunable optical parametric amplifier (OPA), speckle illumination, and quantitative phase imaging based on quadriwave lateral shearing interferometry (QLSI). The high-power OPA provides the peak power required for efficient nonlinear excitation. Speckle illumination distributes the optical energy over the objective back pupil and mitigates coherent imaging artifacts. QLSI enables the simultaneous measurement of the amplitude and phase of the CARS field, thereby allowing separation of resonant and non-resonant contributions, without the need for an external reference beam. This unique combination enables practical phase-resolved CARS imaging over a field of view exceeding $60 \times 60~\text{\textmu m}^2$ at a frame rate of 1.4 Hz. We illustrate the approach by acquiring hyperspectral images of microplastics and liver steatosis across the entire CH-stretching region.
Comments5 figures, 20 pages
