Freudiger Christian W, Min Wei, Holtom Gary R, Xu Bingwei, Dantus Marcos, Xie X Sunney
Department of Physics, Harvard University, Cambridge (MA) ; Department of Chemistry and Chemical Biology, Harvard University, Cambridge (MA).
Nat Photonics. 2011;5(2):103-109. doi: 10.1038/nphoton.2010.294. Epub 2011 Jan 16.
Label-free microscopy with chemical contrast and high acquisition speed up to video-rate has recently been made possible by stimulated Raman scattering (SRS) microscopy. While SRS imaging offers superb sensitivity, the spectral specificity of the original narrowband implementation is limited, making distinguishing chemical species with overlapping Raman bands difficult. Here we present a highly specific imaging method that allows mapping of a particular chemical species in the presence of interfering species based on tailored multiplex excitation of its vibrational spectrum. This is done by spectral modulation of a broadband pump beam at a high-frequency (>1MHz), allowing detection of the stimulated Raman gain signal of the narrowband Stokes beam with high sensitivity. Using the scheme, we demonstrate quantification of cholesterol in the presence of lipids, and real-time three-dimensional spectral imaging of protein, stearic acid and oleic acid in live C.elegans.
受激拉曼散射（SRS）显微镜最近实现了具有化学对比度且采集速度高达视频速率的无标记显微镜技术。虽然SRS成像具有极高的灵敏度，但原始窄带实现方式的光谱特异性有限，使得区分具有重叠拉曼带的化学物质变得困难。在此，我们提出一种高特异性成像方法，该方法基于对特定化学物质振动光谱的定制多重重激发，能够在存在干扰物质的情况下对其进行映射。这是通过在高频（>1MHz）对宽带泵浦光束进行光谱调制来实现的，从而能够高灵敏度地检测窄带斯托克斯光束的受激拉曼增益信号。利用该方案，我们展示了在存在脂质的情况下对胆固醇的定量分析，以及对线虫体内蛋白质、硬脂酸和油酸的实时三维光谱成像。
