Raman Scattering in Solids

Light can be scattered either elastically or inelastically. Raman scattering is an inelastic process. From the macroscopic point of view an incoming photon is scattered at the lattice. This process induces a phonon in the solid and reduces the energy of the photon by the energy lost in the scattering event. However, this description implies a direct interaction of the photon and the phonon. Such an interaction is very improbable and has not been experimentally verified yet. The Raman process as it occurs in solid states involves the excitation of an electron (Fig. 1).