Gao Xin, Qian Naixin, Min Wei
Department of Chemistry, Columbia University, New York, NY, 10027.
J Phys Chem C Nanomater Interfaces. 2025 Mar 27;129(12):5789-5797. doi: 10.1021/acs.jpcc.5c00655. Epub 2025 Mar 13.
Stimulated Raman scattering (SRS) microscopy has revolutionized chemical bond imaging, particularly in biomedicine. However, since its invention in 2008, the theoretical underpinnings of its exceptional sensitivity-surpassing conventional Raman microscopy-have remained largely unexplored. While empirical advancements have driven its success in the following decade, a quantitative understanding of why SRS microscopy performs so effectively has been lacking. This Perspective addresses the knowledge gaps and misconceptions in the field, offering a fundamental theoretical framework for SRS microscopy. Building on recent quantum electrodynamics treatments, we analyze the absolute detection limits of Raman microscopy using a spatiotemporal diagram. Our analysis reveals that spontaneous Raman scattering and stimulated Raman scattering occupy complementary spatiotemporal domains, with the crossover boundary aligning with the length and time scales relevant to bioimaging. Our first-principles theory demonstrates that SRS excels in high spatiotemporal regimes, explaining its unparalleled ability to image chemical bonds, which inherently demand high spatial and temporal resolution. Furthermore, we clarify that SRS spectroscopy and SRS microscopy, though rooted in the same SRS process, operate on distinct principles, serve different purposes, and should not be viewed as natural extensions of one another.
受激拉曼散射(SRS)显微镜彻底改变了化学键成像技术,尤其是在生物医学领域。然而,自2008年发明以来,其卓越灵敏度(超越传统拉曼显微镜)的理论基础在很大程度上仍未得到探索。尽管在接下来的十年中,经验性的进展推动了它的成功,但一直缺乏对SRS显微镜为何能如此有效工作的定量理解。这篇综述文章解决了该领域的知识空白和误解,为SRS显微镜提供了一个基本的理论框架。基于最近的量子电动力学处理方法,我们使用时空图分析了拉曼显微镜的绝对检测极限。我们的分析表明,自发拉曼散射和受激拉曼散射占据互补的时空域,其交叉边界与生物成像相关的长度和时间尺度一致。我们的第一性原理理论表明,SRS在高时空区域表现出色,解释了其成像化学键时无与伦比的能力,而化学键成像本身就需要高空间和时间分辨率。此外,我们阐明,SRS光谱学和SRS显微镜虽然都基于相同的SRS过程,但操作原理不同,服务目的不同,不应被视为彼此的自然延伸。