  Analogue gravity enables the study of fields on curved spacetimes in the
laboratory. There are numerous experimental platforms in which amplification at
the event horizon or the ergoregion has been observed. Here, we demonstrate how
optically generating a defect in a polariton microcavity enables the creation
of one- and two-dimensional, transsonic fluid flows. We show that this highly
tuneable method permits the creation of sonic horizons. Furthermore, we present
a rotating geometry akin to the water-wave bathtub vortex. These experiments
usher-in the possibility of observing stimulated as well as spontaneous
amplification by the Hawking, Penrose and Zeld'ovich effects in fluids of
light.
