Observation of Mechanical Faraday Effect in Gaseous Media

We report the experimental observation of rotation polarization plane light propagating in a gas fast-spinning molecules (molecular super-rotors). In observed effect, related to Fermi's prediction "polarization drag" by rotating medium, vector linear tilts direction molecular due rotation-induced difference refractive indices for left and right circularly polarized components. use an optical centrifuge bring sample ultrafast unidirectional measure drag angles order 0.2 milliradians number gases under ambient conditions. demonstrate all-optical control magnitude direction, investigate robustness mechanical Faraday effect with respect collisions.