Breaking the degeneracy of nematic liquid crystals by means of actuated anisometric paramagnetic colloids

We demonstrate experimentally that the director of a planar nematic liquid crystal cell with degenerated azimuth can be resolved by means of sparse paramagnetic inclusions actuated upon by weak magnetic fields. The use of ellipsoidal particles enables the characterization of the reorientation of the mesogen following particle rotation by means of a simple elastic model. Complex structures like targets and double-armed helices can be generated and controlled by tuning an out-of-plane electric field.