Evaluation of small scattering defects densities by laser scattering tomography: application to levitated glasses

A specific experimental Laser Scattering Tomography (LST) acquisition procedure is presented. It is adapted to the characterization of materials containing scattering defects ranging from 1 to 102/mm3. The technique makes it possible to obtain good resolution within a volume chosen to contain a statistically significant defect density. This method is used to show that the gas levitation technique makes it possible to significantly decrease scattering defects in glasses. In parallel, individual study of defects in such glasses is also presented