This paper compares three new Raman techniques for fiber forensics.
In this study the authors proposed three novel Raman techniques to expand capabilities for non-destructive dyed-fiber forensics: THz Raman spectroscopy (TRS), integrating-cavity-enhanced Raman spectroscopy (ICERS), and deep-UV Raman spectroscopy (DUVRS). The authors report on their attempts to apply these techniques to a variety of dyed-nylon fibers and report on the results of each technique, with a particular focus on the dyes Acid Red 337 and Acid Yellow 49. The authors find that none of the dyes tested had discernible THz peaks but that they do impact the peak positions of the host fabric’s THz spectrum. For ICERS, the authors find that light absorption overwhelms any possible cavity enhancement, making the technique unusable for most dyed fabrics when using UV/VIS excitation. However, NIR excitation may still prove beneficial, but a new cavity material (with a higher NIR reflectance) is needed. Finally, the authors tested DUVRS but found that, for all the dyed fibers tested, the DUV excitation resulted in rapid photodegradation, making the technique unusable for non-destructive forensics. (Published Abstract Provided)