SURFACE-ENHANCED RAMAN SCATTERING
SURFACE-ENHANCED RAMAN SCATTERING
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DOI：
10.1007/1-4020-4611-1_12
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
T. Vo‐Dinh;Fei Yan
中科院分区：
文献类型：
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作者：
T. Vo‐Dinh;Fei Yan
1928年，拉曼爵士记录了非弹性光散射现象。分子散射的辐射包含与入射辐射频率相同的光子，但也可能包含频率变化或移位的光子。这种效应非常微弱——大约百万分之一（0.0001%）的光子会以与原始波长略有偏移的波长从样品中散射出去。这个过程后来以他的名字命名，频率的移动被称为拉曼效应，频率移动的光被称为拉曼辐射。拉曼光谱基于振动跃迁，产生非常窄的光谱特征，这是所研究样品的特征。因此，它一直被认为是鉴定化学和生物样品以及阐明分子结构，表面过程和界面反应的有价值的工具。尽管有这些优点，但拉曼散射的缺点是效率极低。与基于发光的过程相比，拉曼光谱具有固有的小截面（例如每分子10-30cm2），因此排除了在低浓度水平下检测分析物的可能性，而无需特殊的增强过程。一些信号增强模式包括共振拉曼散射和非线性过程，如相干反斯托克斯拉曼散射。然而，对高功率、多波长激发源的需求限制了这些技术的广泛应用。
AbstractIn 1928, Sir C.V. Raman documented the phenomenon of inelastic light scattering1. Radiation scattered by molecules contains photons with the same frequency as the incident radiation, but may also contain photons with changed or shifted frequency. This effect is very weak - approximately one photon out of a million (0.0001%) will scatter from that sample at a wavelength slightly shifted from the original wavelengths. The process was later named after him, with the shifting of frequency referred to as the Raman effect and the frequently-shifted light as Raman radiation. Raman spectroscopy is based on vibrational transitions that yield very narrow spectral features which are characteristic of the investigated sample. Thus, it has long been regarded as a valuable tool for the identification of chemical and biological samples as well as the elucidation of molecular structure, surface processes, and interface reactions. Despite such advantages, Raman scattering suffers the disadvantage of extremely poor efficiency. Compared to luminescence-based processes Raman spectroscopy has an inherently small cross-section (e.g. 10-30cm2per molecule), thus precluding the possibility of analyte detection at low concentration levels without special enhancement processes. Some modes of signal enhancement have included resonance Raman scattering and nonlinear processes such as coherent anti- Stokes Raman scattering. However, the need for high-power, multiplewavelength excitation sources has limited the widespread use of these techniques.