Resonance CARS in Narrow Gap Semiconductors

Abstract

Coherent anti-Stokes Raman scattering due to spin transitions of free carriers in narrow gap semiconductors is discussed. The basic results of the electrodynamic theory of optical four-wave mixing and of the quantum mechanical calculation of the third-order non-linear susceptibility χ(3) are briefly reported in the context of the particular properties of narrow gap semiconductors. The enhancement of the Raman-like resonances of χ(3) for photon energies close to the fundamental gap is demonstrated and interferences of Raman and one-photon interband transitions are discussed. Applications of the method to epitaxial films of narrow gap semiconductors and to quantum well structures are presented.