(see also Movie S6)
We imprint a space structured vector beam comprising all polarization states, known either as full "Poincaré beam" or "skyrmion".
The mapping of the polarization pattern onto the Poincaré sphere highlights how real-space circles and radii are conformally mapped to the parallels and meridians of the sphere, respectively. The ultrafast imaging of such an initial state reveals its evolution due to the xy-anisotropy splitting along preferential crystallographic or stress/strain directions.
The evolution is reproduced by a numerical model (in the figure), where we report the association of a real-space circular corona to a "topological belt". The fundamental effect of the xy-anisotropy consists in the dynamical twist of the "topological belt".
Donati et al, Twist of generalized skyrmions and spin vortices in a polariton superfluid, Proc. Natl. Acad. Sci. USA 113, 14926 (2016)