Light-scattering evolution from particles to regolith

•We use the RT-CB method to examine how gross light-scattering properties evolve as particle size increases.•The transition from a wavelength-sized particle to a large particle is not monotonic.•Backscattering properties associated with the CB mechanism appear to have a peak value before decaying asymptotically.

The radiative-transfer coherent-backscattering (RT-CB) model is unique among light-scattering methodologies as it can be used to calculate accurate light-scattering properties of sparsely populated particle volumes with sizes ranging from subwavelength to infinity. We use the RT-CB model to examine the evolution of light-scattering properties as a volume of particles increases from wavelength-sized to several hundreds of wavelengths. We examine the evolution of light-scattering intensity phase function and polarization, as well as linear and circular polarization ratios. We confirm the expected trends for backscattering features to shift to smaller phase angles as the volume increases. In addition, we also see the amplitude of these features increases to some maximum for volumes having size parameters kR~100, before decaying to less than half this amplitude as their volumes approach infinity.