Optical Vortex Core Switching in Spinor Polariton Condensates

Vortices are topological objects carrying quantized orbital angular momentum, also known as topological charge, and have been widely studied in many physical systems for their applicability in information storage and processing. Here we focus on vortices in semiconductor microcavity polariton condensates. In systems with spin degree of freedom the elementary excitations are so called half-vortices. A half-vortex carries a quantum circulation only in one of the two spin components. It has lower energy in comparison with a full-vortex and, importantly, has a circularly polarized density peak in the vortex core region, while elsewhere the condensate is linearly polarized. We demonstrate the spontaneous formation of localized half-vortices in spinor polariton condensates, non-resonantly excited by a linearly polarized ring pump. The pseudospin structure of the condensate includes a TE-TM splitting leading to effective spin-orbit coupling, resulting in solutions with broken cylindrical symmetry. The cross-interaction between different spin components provides an efficient method to realize optical vortex core switching between left- and right-circularly polarized states. This switching can be easily detected by measuring the polarization resolved intensity in the vortex core region and it can also be applied to higher order half-vortex states.