Work

Robotic Raman‐OCT for Non‐Destructive Visualization of Concealed Latent Fingerprints and Trace‐Residue Profiling

Year: 2025

Type: article

Abstract: Latent fingerprints concealed beneath opaque barriers or containing chemical residues require a dual‐capability approach: non‐destructive visualization of ridge structures and precise identification of trace substances. Here, a robotic‐assisted Raman‐optical coherence tomography (R 2 ‐OCT) system is introduced that seamlessly integrates structural and molecular imaging into a unified, non‐destructive workflow. A spectral‐domain OCT probe (10 µm lateral, 6 µm axial resolution) and a 785 nm fiber‐coupled Raman probe are rigidly mounted on a six‐axis robotic arm, reliably localizing residue particles down to ≈100 µm for Raman targeting. An initial OCT scan reconstructs a 3D volume and generates curvature‐corrected en‐face images that clearly reveal concealed ridge patterns and precisely localize micrometer‐scale residues. Guided by these coordinates, the robotic arm autonomously repositions and auto‐focuses the Raman probe, acquiring spectra in ≈1 s per site. Proof‐of‐concept studies on latent prints doped with sodium carbonate, calcium carbonate and potassium sorbate confirm accurate residue localization; mixed‐residue tests further discriminate potassium nitrate, potassium chlorate and sulfur. Complete characterization of six discrete particles is achieved in ≈20 s, over an order of magnitude faster than conventional raster‐based Raman mapping. R 2 ‐OCT offers a rapid, non‐destructive tool for simultaneous fingerprint visualization and chemical profiling, advancing forensic, biomedical, and material applications.

Source: Small Methods

DOI: 10.1002/smtd.202501251