Model-Based Optimization of Laser Excitation and Detection Improves Spectral Contrast in Noninvasive Diffuse Raman Spectroscopy
Model-Based Optimization of Laser Excitation and Detection Improves Spectral Contrast in Noninvasive Diffuse Raman Spectroscopy
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DOI：
10.1177/00037028211072900
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发表时间：
2022-04-30
影响因子：
3.5
通讯作者：
Notingher, Ioan
中科院分区：
文献类型：
--
作者：
Dooley, Max;Paterson, Thomas;Notingher, Ioan
空间偏移拉曼光谱(SORS)是一种对光学混浊样品进行亚表面分子分析的强大技术。光传播的数值模拟已经被用来研究当成像感兴趣的区域位于聚合物块状材料表面以下0-4.5 mm时，改善光谱对比度和信噪比的机会。二维和三维建模结果表明，当分析样品表面下有限横向尺寸的特定感兴趣区域(ROI)时，与传统的将检测器或激光器保持在中心点(居中的SOR)的方法相比，在与ROI中心点相反的方向上偏移激光光源和检测器可以增加光谱对比度。概述的建模结果已经使用样品表面下具有反式二苯乙烯ROI(圆柱体)的本体聚合物样品进行了实验验证。结果表明，对激光激发点和检测点的空间构型进行建模可以优化仪器的结构，使性能比传统的居中SORS有显著的提高(最高可达2.25倍)。例如，可以使用坚固的光纤探头、可移动的光学器件或用于特定应用的灵活的空间光调制器仪器来实现这种最佳解决方案。
Spatially offset Raman spectroscopy (SORS) is a powerful technique for subsurface molecular analysis of optically turbid samples. Numerical modeling of light propagation has been used to investigate opportunities for improving spectral contrast and signal to noise ratio when imaging regions of interest located 0-4.5 mm below the surface in polymer bulk material. Two- and three-dimensional modeling results demonstrate that when analyzing a certain region of interest (ROI) of finite lateral dimensions below the sample surface, offsetting both the laser source and detector in opposite directions from the central point of the ROI can increase the spectral contrast as compared to conventional SORS approach where the detector or the laser source is maintained at the central point (centered SORS). The outlined modeling results have been validated experimentally using a bulk polymer sample with a trans-stilbene ROI (cylinder) below the sample surface. The results show that modeling of the spatial configurations of laser excitation and detection points can be used to optimize the instrument configuration to achieve significant improvements (up to 2.25-fold) in performance over the conventional centered SORS. Such optimal solutions can then be implemented, for example, using robust fiber optic probes, moveable optics, or flexible spatial light modulator instruments for specific applications.