The inelastic scattering of light was initially predicted [1] in 1923; however,it was not until 1928 that Raman performed the first experiment [2] and confirmed the predictions of Smekal and thus obtained the Nobel Prize in Physics in 1930. Unlike Rayleigh scattering, which corresponds to an elastic light scattering (conservation of energy) [3], Raman scattering is an inelastic process due to various elementary excitations (quasi-excitations) where energy

can be lost or gained in the scattering process. Excitations responsible for Raman scattering can be for example the internal vibrational modes in a molecule (vibrons), phonons in an ordered crystal structure (lattice vibrations) or magnons in systems with magnetic order transitions.