Spatially-offset Raman spectroscopy (SORS) is gaining an increasing popularity in detection of analytes through barriers. SORS can be applied in a number of different excitation modes and head-to-head comparison of different SORS modes are limited in the literature. In this study, a custom system that is capable of switching between two spatially offset Raman excitation modes, namely inverse (iSORS, ring) and diffuse (dSORS, enlarged flat-top circle), were compared at the same power for depth-probing Raman spectroscopy applications. Specifically, depth of detection, signal-to-noise ratio, and intensity ratio as a measure of elimination of barrier contribution to the Raman spectra were compared between the two methods. Transparent and opaque polymeric materials as well as skin tissue were used as barriers to characteristic Raman peaks from other polymers, pharmaceutical tablets or joint-borne gout crystals. Results indicated that diffuse SORS mode provides signal collection from depth layers at significantly greater intensities and at higher signal-to-noise ratio when compared to iSORS. On the other hand, iSORS generally provided a higher depth layer to barrier layer intensity ratio, indicating that iSORS is more effective than diffuse SORS in terms of the elimination of barrier layer contribution. We also demonstrate that barrier signal can be eliminated in diffuse-SORS mode as well by reducing collection zone area using a variable pinhole. Overall, the results of this study indicate that diffuse SORS mode to be useful in detecting the analyte particularly when the barrier layer is thick, or, when presence of barrier layer peaks in a spectrum does not confound the analysis.

空间偏移拉曼光谱（SORS）在通过障碍物检测分析物方面越来越受欢迎。SORS可以应用于多种不同的激励模式，并且不同SORS模式的头对头比较在文献中受到限制。在这项研究中，将一个能够在两个空间偏移拉曼激发模式之间切换的自定义系统，即反向（iSORS，环形）和散射（dSORS，放大的平顶圆）在相同的功效下进行了深度探测拉曼光谱学应用。具体而言，在两种方法之间比较了检测深度，信噪比和强度比，以消除对拉曼光谱的势垒贡献。透明和不透明的聚合材料以及皮肤组织被用作阻挡其他聚合物，药物片剂或关节携带的痛风晶体的特征拉曼峰的屏障。结果表明，与iSORS相比，漫射SORS模式可以以更高的强度和更高的信噪比从深度层收集信号。另一方面，iSORS通常提供更高的深度层与势垒层强度比，这表明iSORS在消除势垒层贡献方面比扩散SORS更有效。我们还证明，通过使用可变针孔减小收集区面积，也可以在漫射SORS模式下消除屏障信号。全面的，