US Patent 7911604 Security screening using raman analysis

Method and apparatus for screening objects using Raman scattering methods to detect the presence of predefined substances or classes of substances. The predefined substances may be hazardous, toxic, or explosive. Radiation is supplied to an incident region of an object. Scattered light is collected from a collection region on the surface of the object spaced from the incident region. The characteristics of the scattered light include Raman features related to the predefined substances. The Raman features allow the presence, or not, of the predefined substances to be determined.