Inelastic light scattering for the investigations of nano- and meso-structures

Abstract
At an intermediate level between the atomic and the macroscopic scales, nano- and meso-structures crucially determine the properties of nanostructured materials. Such materials, either aggregations of nanoparticles, weakly or strongly interacting, or matrices containing nanoparticles, are of great interest for nanotechnologies. Inelastic light scattering, either coherent Brillouin scattering from traveling vibrational excitations or incoherent low frequency Raman scattering from non traveling excitations, is a powerful probe intrinsically tuned at a mesoscopic scale. Its potential is shown by several examples: tin particles embedded in a silica film, porous silicon, cluster assembled carbon films, sintered polytetrafluoroethilene particles, and single walled carbon nanotubes. Nanoparticle properties and inter-particle interactions are probed either directly or through the properties of the effective homogeneous medium in which acoustic wave propagation occurs.