5. Biology and medicine

5.1 Biology

Terahertz waves are a non-invasive tool for characterizing certain properties of biological matter. Indeed, terahertz waves can enter into resonance with the vibration modes of molecules. These are vibrations of large portions of the molecular structure. Since these modes of vibration depend on the shape of the molecule and changes in that shape, terahertz spectroscopy provides information on their geometry and composition. Numerous organic molecules have been studied in this way, such as benzoic acid, which exhibits beautiful spectral signatures in the terahertz range, or synthetic RNA, whose polyadenyl and polycytidylic acid chains show different terahertz absorptions. Obtaining information on the shape of the molecule is perfectly illustrated by the terahertz spectroscopy...