The presence of polarization splitting of exciton-polariton branches in
planar semiconductor microcavities has a pronounced effect on vortices in
polariton condensates. We show that the TE-TM splitting leads to the coupling
between the left and right half-vortices (vortices in the right and left
circular components of the condensate), that otherwise do not interact. We
analyze also the effect of linear polarization pinning resulted from a fixed
splitting between two perpendicular linear polarizations. In this case,
half-vortices acquire strings (solitons) attached to them. The half-vortices
with strings can be detected by observing the interference fringes of light
emitted from the cavity in two circular polarizations. The string affects the
fringes in both polarizations. Namely, the half-vortex is characterized by an
asymmetric fork-like dislocation in one circular polarization; the fringes in
the other circular polarization are continuous, but they are shifted by
crossing the string.Comment: 4 pages, 2 figs, Optics of Excitons in Confined Systems 11 (Madrid,
7-11 september 2009