MDI’s StreetLab portable substance identification system utilizes laser-based Raman technology to deliver fast, accurate, low-cost identification of unknown substances seized in the field. It relies on inelastic scattering, called Raman scattering, of monochromatic light from a laser in the visible near infrared or near ultraviolet range. Phonons or other excitations in the system are absorbed or emitted by the laser light, resulting in the energy of the laser photons being shifted up or down. The shift in energy gives information about the phonon modes in the system.

Typically, a sample is illuminated with a laser beam. Light from the illuminated spot is collected with a lens and sent through a monochromator. Wavelengths close to the laser line (due to elastic Rayleigh scattering) are filtered out and those in a certain spectral window away from the laser line are dispersed onto a detector. Since vibrational information is very specific for the chemical bonds in molecules, it provides a fingerprint by which the molecule can be identified.

This technology analyzes and identifies a broad range of drugs and explosives in seconds, without sample destruction or subjective interpretation.