Spontaneous vortices in optically shaped potential profiles in semiconductor microcavities

We investigate the spontaneous formation of quantized vortices in microcavity polariton high density phases. Condensates formed in the optical parametric oscillator excitation scheme reveal single vortices in the case of a ring-shaped optical potential or in the presence of natural photonic disorder. We further investigate the dynamics of vortex formation for resonantly injected polaritons and observe the formation of vortex-antivortex pairs, but no single vortices. The observed effects are explained by the interplay between breaking of y↦−y reflection symmetry in the system and conservation of optical angular momentum.