US Patent 7408637 Entangled photon spectroscopy for stand-off detection and characterization

A system for and method of detecting and characterizing materials using entangled photons is presented. The material may be at a great distances from the detector and may be biological material, complex organic compounds, or inorganic chemicals. The disclosed system and method provide advantages over traditional techniques in that they are largely impervious to atmospheric reduction of probing radiation and in that less probing radiation is required. The reduced probe energy requirement allows for detecting and characterizing sensitive material with significantly reduced material bleaching compared with traditional techniques.