SUPPRESSION OF MULTIPLE-SCATTERING IN PHOTON-CORRELATION SPECTROSCOPY

While static and dynamic light scattering experiments have been a major source of information about the structure and dynamics of dilute colloidal systems or macromolecular solutions, their application to more concentrated samples is severely limited by multiple scattering. Our dual-colour photon correlation experiment achieves very efficient isolation of singly scattered light by cross-correlation over the full range of scattering angles between 20-degrees and 140-degrees. The dual-colour cross-correlation technique immediately yields dynamic structure factors, which are not affected by multiple scattering. A second use of dynamic dual-colour cross-correlation measurements is in estimating the ratio of singly and multiply scattered light. Finally the experiment allows very successful recovery of static information from dynamic light scattering data on concentrated samples with central two-body interaction forces.