  We experimentally demonstrate a technique for the generation of optical beams
carrying orbital angular momentum using a planar semiconductor microcavity.
Despite being isotropic systems, the transverse electric - transverse magnetic
(TE-TM) polarization splitting featured by semiconductor microcavities allows
for the conversion of the circular polarization of an incoming laser beam into
the orbital angular momentum of the transmitted light field. The process
implies the formation of topological entities, a pair of optical half-vortices,
in the intracavity field.
