  The application of dynamic light scattering to soft matter systems has
strongly profited from advanced approaches such as the so-called modulated 3D
cross correlation technique (mod3D-DLS) that suppress contributions from
multiple scattering, and can therefore be used for the characterization of
turbid samples. Here we now extend the possibilities of this technique to allow
for depolarized light scattering (Mod3D-DDLS) and thus obtain information on
both translational and rotational diffusion, which is important for the
characterization of anisotropic particles. We describe the required optical
design and test the performance of the approach for increasingly turbid samples
using well defined anisotropic colloidal models systems. Our measurements
demonstrate that 3D-DDLS experiments can be performed successfully for samples
with a reduced transmission due to multiple scattering as low as 1\%. We
compare the results from this approach with those obtained by standard DDLS
experiments, and point out the importance of using an appropriate optical
design when performing depolarized dynamic light scattering experiments with
turbid systems.
