  The rotational response of quantum condensed fluids is strikingly distinct
from rotating classical fluids, especially notable for the excitation and
ordering of quantized vortex ensembles. Although widely studied in conservative
systems, the dynamics of rotating open-dissipative superfluids such as
exciton-polariton condensates remain largely unexplored, as it requires
high-frequency rotation whilst avoiding resonantly driving the condensate. We
create a rotating polariton condensate at GHz frequencies by off-resonantly
pumping with a rotating optical stirrer composed of the time-dependent
interference of two frequency-offset, structured laser modes. Acquisition of
angular momentum exceeding the critical $1\hbar$/particle is directly measured,
accompanied by the deterministic nucleation and capture of quantized vortices
with a handedness controlled by the pump rotation direction. The demonstration
of controlled optical rotation of a spontaneously formed polariton condensate
enables new opportunities for the study of open-dissipative superfluidity,
ordering of non-Hermitian quantized vortex matter, and topological states in a
highly non-linear, photonic platform.
