  Vector vortex beams are a class of optical beams with singularities in their
space-variant polarization. Vector vortex beam lasers have applications in many
areas including imaging and communication, where vertical-cavity lasers
emitting Gaussian beams have been most widely used so far. Generation of vector
vortex beams from vertical-cavity lasers has required external control or
modulation. Here, by utilizing a polarization-selective subwavelength grating
as one of the reflectors in a vertical semiconductor microcavity, we design the
spin textures of the polariton mode and demonstrate polariton lasing in a
single-mode, radially polarized vector vortex beam. Polarization and phase
distributions of the emission are characterized by polarization-resolved
imaging and interferometry. This method of vector vortex laser beam generation
allows low threshold power, stable single-mode operation, scalability, and
on-chip integration, all of which are important for applications in imaging and
communication.
