Non-Linear Raman Scattering in I-III2-VI4 Compounds

Abstract

The paper presents an experimental substantiation of the theory (based on the optical vibration anharmonism) of non-linear Raman scattering (RS) in defective II-III2-VI4 compounds. In the transparency region of those compounds the anharmonicity assures processes of direct photon-phonon interaction resulting in the independence of RS characteristics upon the free carrier concentration. When the laser quantum energy approaches the band gap Eg an effective thermalization of the absorbed radiation takes place which in one's turn gives rise to the anharmonic generation of two or more phonons by a laser photon. These phenomena are shown to result in a non-linear dependence of the RS intensity upon the laser beam power.