Since polarimetry has extended its use for the study of scattering from surfaces and tissues, Spectralon, a white reflectance standard, is acquiring the role of a polarimetric standard. Both the behavior of Spectralon as a Lambertian surface and its performance as a perfect depolarizer are analyzed in detail. The accuracy of our dynamic polarimeter, together with the polar decomposition to describe the Mueller matrix (MM) depolarizing action, combine to produce a powerful tool for the proper analysis of this scattering surface. Results allowed us to revisit, for confirmation or revision, the role of some MM elements, as described in the bibliography. The conditions under which it can be considered a good Lambertian surface are specified in terms of incidence and scattering angle and verified over a large wavelength range.

The influence of the degree of purity of a silicon nanoparticle on its resonances, either electric or magnetic, is assessed by using Mie theory as well as finite-element simulations. In particular, it is shown that the main effect of the increase of absorption due to the pollutants is observed in the magnetic resonances. Concerning Kerker’s conditions for the directionality of the scattering [J. Opt. Soc. Am. 73, 765 (1983)], it is found that both are strongly shifted when the material’s purity is varied. Resistive losses confirm the quenching of magnetic resonances, showing that the region of influence in the magnetic dipole resonance is much larger than in the electric one, although it has been found that losses are not critical for silicon content over 99.50%.