Optical properties of a dispersion of randomly oriented identical aggregates of spheres deposited on a plane surface

Our previous theory for calculating the scattering pattern from a single ag gregate of spheres deposited on a dielectric substrate is extended to deal with a dispersion of identical aggregates onto the substrate with a random distribution of their orientations. To this end the definition of the trans ition matrix of an aggregate is generalized to take account of the presence of the substrate; then the transformation properties under rotation of the newly defined transition matrix are used to perform analytically the requi red orientational averages. When the patterns calculated with this theory a re compared with the calculations for a single aggregate, it can easily he seen that the features that reveal the anisotropy of the scatterers are not canceled by the averaging procedure. (C) 1999 Optical Society of America.