A Low-Cost Fiber Optic Visible Microspectrometer for the Small Forensic Science Laboratory

Abstract

The logical first step in any traditional forensic visual examination of trace evidence samples is color comparison. However, comparing the color of two objects to determine if a common origin exists is largely subjective, unless the colors are far apart on the spectrum. To aid in the discrimination process, instrumental methods such as microspectrophotometry have been employed. A number of commercial units have been available over the years to make transmission, reflectance, and fluorescence measurements on these types of evidence, although many of these current and past units are quite costly. This paper describes the use of an Ocean Optics USB-2000+ fiber optic array detector (spectrometer) connected to existing laboratory microscopes and a laptop PC for such measurements. This spectrometer performed more than adequately for the determination of reflectance and transmission visible spectra of glass chips and dyed fibers.