Full control of the libration potential in rotational levitodynamics

Control of the potential energy and free evolution lie at the heart of levitodynamics as key requirements for sensing, wave function expansion, and mechanical squeezing protocols. Here, we experimentally demonstrate full control over the optical potential governing the librational degrees of freedom of a levitated anisotropic nanoparticle. This control is achieved by introducing the degree of polarization as a new tool for rotational levitodynamics. We demonstrate the free rotation of a levitated anisotropic scatterer around its short axis and and we use the rotational degrees of freedom to probe the local spin of a strongly focused laser beam.