Subsurface probing in diffusely scattering media using spatially offset Raman spectroscopy
Subsurface probing in diffusely scattering media using spatially offset Raman spectroscopy
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DOI：
10.1366/0003702053641450
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发表时间：
2005-04-01
影响因子：
3.5
通讯作者：
Parker, AW
中科院分区：
文献类型：
--
作者：
Matousek, P;Clark, IP;Parker, AW
我们描述了一个简单的方法，有效地检索的拉曼光谱的次表层在漫散射介质。该技术是基于收集的拉曼散射光从表面区域横向偏离远离激发激光点上的样品。以这种方式获得的拉曼光谱表现出被研究样品的表面层和次表面层的相对光谱强度的变化。使用多变量数据分析处理数据集以产生单个样品层的纯拉曼光谱，从而提供有效消除表面拉曼散射的方法。该方法适用于检索纯拉曼光谱深度超过那些可与传统的共聚焦显微镜。在该第一可行性研究中，我们区分了由两层组成的漫散射样品内的表面和次表面拉曼信号：在PMMA（聚（甲基丙烯酸甲酯））粉末的一层厚的覆盖层下面的反式芪粉末。没有数值处理的次表面反式芪层的对比度的改善是19倍。潜在的应用包括通过不同的覆盖组织对特定组织的生物医学亚表面探测，例如通过皮肤评估骨质量，提供有效的非侵入性方法来筛查骨退化，其他骨骼疾病诊断和皮肤病学研究，以及材料和催化剂研究。
We describe a simple methodology for the effective retrieval of Raman spectra of subsurface layers in diffusely scattering media. The technique is based on the collection of Raman scattered light from surface regions that are laterally offset away from the excitation laser spot on the sample. The Raman spectra obtained in this way exhibit a variation in relative spectral intensities of the surface and subsurface layers of the sample being investigated. The data set is processed using a multivariate data analysis to yield pure Raman spectra of the individual sample layers, providing a method for the effective elimination of surface Raman scatter. The methodology is applicable to the retrieval of pure Raman spectra from depths well in excess of those accessible with conventional confocal microscopy. In this first feasibility study we have differentiated between surface and subsurface Raman signals within a diffusely scattering sample composed of two layers: trans-stilbene powder beneath a I rum thick over-layer of PMMA (poly(methyl methacrylate)) powder. The improvement in contrast of the subsurface trans-stilbene layer without numerical processing was 19 times. The potential applications include biomedical subsurface probing of specific tissues through different overlying tissues such as assessment of bone quality through skin, providing an effective noninvasive means of screening for bone degeneration, other skeletal disease diagnosis, and dermatology studies, as well as materials and catalyst research.