  We study light scattering by systems combining randomly rough surface and
volume dielectric fluctuations. We introduce a general model including
correlations between surface and volume disorders, and we study the scattering
properties within a single scattering approach. We identify different regimes
of surface and volume dominated scattering depending on length scales
characterizing the surface and volume disorders. For uncorrelated disorders, we
discuss the polarization response of each source of disorder, and show how
polarimetric measurements can be used to separate the surface and volume
contributions in the total measured diffusely scattered intensity. For
correlated systems, we identify two configurations of volume disorder which,
respectively, couple weakly or strongly to surface scattering via
surface-volume cross-correlations. We illustrate these effects on different
configurations exhibiting interference patterns in the diffusely scattered
intensity, which may be of interest for the characterization of complex systems
or for the design of optical components by engineering the degree of
surface-volume correlations.
