The Magnetic eye of the iron tiger
Light polarization from a thin film of ferrofluid obtained with the magnetic field of two cylindrical magnets, placed side by side with poles in opposition. The pattern obtained with the experiment is shown in (a) with the small magnet at the bottom. In (b) we can see the simulation of this pattern magnet using the Fresnel–Kirchhoff diffraction theory. More information about this work can be found in these open access papers: Light Polarization Using Ferrofluids and Magnetic Fields
—Alberto Tufaile Soft Matter Lab, EACH, University of São Paulo