Imaging by Vibration “Signatures”
As the National Institute of Standards and Technology reports, a new method—called “broadband, coherent anti-Stokes Raman spectroscopy—has been developed to do high speed chemical imaging of tissue and cells. “Raman spectroscopy is based on a subtle interplay between light and molecules. Molecules have characteristic vibration frequencies associated with their atoms flexing and stretching the molecular bonds that hold them together. Under the right conditions, a photon interacting with the molecule will absorb some of this energy from a particular vibration and emerge with its frequency shifted by that frequency – this is “anti-Stokes scattering.” Recording enough of these energy-enhanced photons reveals a characteristic spectrum unique to the molecule. This is great for biology because in principle it can identify and distinguish between many complex biomolecules without destroying them and, unlike many other techniques, does not alter the specimen with stains or fluorescent or radioactive tags. MORE
Image Credit: NIST.gov