Due to its high potential level of selectivity using structural information, the Scientific Working Group for the Analysis of Seized Drugs (SWGDRUG) designated it as a Category A method. Raman spectroscopy is increasingly common in the realm of forensic analysis. Raman spectroscopy is a nondestructive, non-invasive technique that can be used to analyse even the smallest sample with very little sample preparation. While water can dwarf the signals of genuine analytes in the infrared, it does not exhibit substantial signals in the Raman spectroscopy. When NIR light sources are utilized (to reduce fluorescence interference), Raman signals may be significantly weaker because scattering is inversely proportional to the fourth power of the incident light's wavelength. At least through some proof-of-concept studies, forensic scientists have begun to use a novel technique called shifted-excitation Raman difference spectroscopy (SERDS) to get around fluorescence interference in the Raman analysis of some forensic evidence. Description The traditional backscattering Raman spectroscopy strategy is reasonable for surface investigation. Although conventional confocal Raman microscopy can be used to analyze subsurface layers if upper layers are transparent, using it to directly analyze a subsurface material through a turbid surface layer can be very challenging. Spatially offset Raman spectroscopy (SORS) has been developed to retrieve subsurface Raman information regardless of whether the surface layer is transparent. This technique has found use in forensic science.