Propagation in pair-correlated distributions of small-spaced lossy scatterers

This is the authors' abstract. We don't add key points for this paper.

Earlier results for coherent attenuation of light by pair-correlated random distributions of dielectric particles of radius a (with separation of closest centers 2b≥2a small compared to wavelength) are generalized to absorbing scatterers with higher refractivity. To facilitate applications, we reduce the total attenuation coefficient (τ) to two terms, one proportional to the absorption cross section of an isolated particle, and one to the scattering cross section times the statistical-mechanics packing correlation function W discussed earlier; each term is also proportional to the same simple function of the first-order coherent phase change. For lossless scatterers, the dependence of W on the volume fraction (W) of particles of radius b accounts for the transparency of correlated distributions at relatively dense packing, as well as for the opacity that arises with looser packing. For lossy scatterers, W (W) determines the relative influence of absorption losses and scattering losses in τ. Even if the scattering losses are the more significant for small W, the absorption losses dominate as W increases; for such cases and moderate refractivity, we show that τ(W) may have a maximum, and determine its value and the corresponding value of W in terms of the cross sections and the form of W.