  The gyrotropic properties of a rotating magnetized plasma are derived
analytically. Mechanical rotation leads to a new cutoff for wave propagation
along the magnetic field and polarization rotation above this cutoff is the sum
of the classical magneto-optical Faraday effect and the mechanico-optical
polarization drag. Exploiting the very large effective group index near the
cutoff, we expose here, for the first time, that polarization drag can be
$10^4$ larger than Faraday rotation at GHz frequency. The rotation leads to
weak absorption while allowing direct frequency control, demonstrating the
unique potential of rotating plasmas for non-reciprocal elements. The very
large rotation frequency of a dense non-neutral plasma could enable
unprecedented gyrotropy in the THz regime.
