Research paper prepared in our group, in collaboration with researchers in Macquire University in Australia, and University Autónoma de Madrid in Spain, has been published in Physical Review Letters.
The paper, entitled Isotropically polarized speckle patterns, discusses a surprising effect emerging when the so-called helical light (e.g. left- or right-hand circularly polarized planewave) illuminates a solution of dielectric nanoparticles. We show that if the electric and magnetic polarizabilities of the scatterers match (e.g. for submicron Si nanoparticles), the electric and magnetic dipoles induced in them become aligned, and the light scattered by the solution exhibits a complete circular polarization and, at the same time, a speckle pattern of the scattering intensity.
This effect can be used either as an engineering tool, to design more resilient information-carrying light beams, or to characterize the magnetic activity of random media composed of non-magnetic scatterers.