Light Scattering Angular Correlation of Spherical Droplets Containing Inclusions

Micrometer-size glycerol droplets containing spherical latex inclusions are levitated in an electrodynamic trap. The scattering phase functions of such particles undergo random fluctuations with time. We measure the intensities at two (near-forward and near-backward) scattering angles and find them to have strong positive correlations during some time periods and strong negative correlations during other time periods. Characteristic time constants of the correlations are on the order of seconds. We compare our experimental results with correlations predicted by two simple scattering models and suggest that these correlation changes are associated with the diffusion of inclusions within the host droplet, rather than interference effects between the inclusions.