Excitation of Vortices in Semiconductor Microcavities
  We predict that the transverse electric-magnetic polarization splitting of exciton-polaritons allows a simple technique for the generation of polariton vortices of winding number 2 in semiconductor microcavities. The vortices can be excited by circularly polarized light having no orbital angular momentum and observed as phase vortices in the opposite circular polarization or directly as linear polarization vortices. The prediction is explained by a simplified analytical linear model and shown fully with a numerical model based on the Gross-Pitaevskii equations, which includes the non-linear effects of polariton-polariton interactions. 
T C H Liew, A V Kavokin, I A Shelykh