Work

When light meets particles that are smaller than the light’s wavelength, the light spreads in different directions. This occurs, for example, when light packets—photons—encounter molecules in a gas. In 1928 Venkata Raman discovered that a small portion of the scattered light acquires other wavelengths than that of the original light. This is because some of the incoming photons’ energy can be transferred to a molecule, giving it a higher level of energy. Among other things, the phenomenon is used to analyze different types of material.