Spatially offset Raman spectroscopy (SORS) provides a new powerful method for non-invasive detecting of the substance in containers. However, it takes a long time to collect spectra at different offset distances and needs multivariate analysis, which is not suitable for rapid on-site detection. In this paper, a rapid two-step SORS detection method based on the Raman scattering photons transmission and distribution simulated by Monte Carlo is proposed. Commonly used packaging materials such as plastic and glass are considered, the ‘plastic/glass-drug’ double-layer samples were constructed and the Raman intensities of each layer of samples at different offset distances were simulated. The Raman spectra of actual samples at different offset distances were collected by a self-developed portable confocal Raman spectrometer with additional collection probe. The relationship between the optimal offset distance of two-step SORS and the thickness of different materials container wall was investigated. Actual measurement results are consistent with simulation results. The feasibility of decreasing the detection steps and shortening the detection time by pre-selecting the optimal offset distance was studied. Based on this, we propose the two-step SORS technique that only needs to collect spectra at two pre-selected locations with a simple data processing method to quickly obtain the Raman spectrum of the substance in the container. Two-step SORS technique can greatly reduce the detection steps, improve the detection efficiency, and achieve non-invasive rapid detection.

空间偏移拉曼光谱 (SORS) 为无创检测容器中的物质提供了一种新的强大方法。但不同偏移距离的光谱采集时间长，需要多变量分析，不适合现场快速检测。本文提出了一种基于蒙特卡罗模拟的拉曼散射光子传输和分布的快速两步SORS检测方法。考虑了塑料、玻璃等常用包装材料，构建了“塑料/玻璃-药物”双层样品，模拟了不同偏移距离下各层样品的拉曼强度。实际样品在不同偏移距离下的拉曼光谱由自行研制的带有附加采集探头的便携式共焦拉曼光谱仪采集。研究了两步SORS的最佳偏移距离与不同材料容器壁厚度的关系。实际测量结果与仿真结果一致。研究了通过预选最佳偏移距离减少检测步骤、缩短检测时间的可行性。基于此，我们提出了两步SORS技术，只需在预先选定的两个位置采集光谱，采用简单的数据处理方法，即可快速获得容器内物质的拉曼光谱。两步SORS技术可以大大减少检测步骤，提高检测效率，