Abstract: Optical imaging technology is important for the detection and examination of physical evidence, and has the advantages of non-destructive, in situ and rapid analysis. In recent years, with the continuous development of optical imaging technology, some new techniques and methods have been introduced into the forensic science and put into application. Optical coherence tomography (OCT) is new in forensics and performs high-resolution, cross-sectional tomographic imaging of the internal microstructure in materials and tissues, and without any damages to the evidence. This paper first introduces a custom-built three-dimensional OCT imaging system, and then presents three novel applications by utilizing this system, including car paint analysis, latent fingerprint visualizing and hair follicle analysis. These results show that OCT technology is very suitable for physical evidence examination because of its characteristics of non-destructive high-resolution subsurface imaging. As a novel technology for forensic investigation, OCT imaging obtains internal structural information and new optical features of samples and extracts. In the future, it is expected to be portable and miniaturized and be applied in crime scene investigation.

Key words: optical coherence tomography, forensic science, paint examination, latent fingerprint development, hair follicles imaging