  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.
