# Circular polarization reversal of half-vortex cores in polariton condensates

## TL;DR

This paper investigates the formation and control of half-vortices in polariton condensates, demonstrating all-optical switching of their circular polarization states via spin-orbit coupling effects.

## Contribution

It introduces a novel method for all-optical switching of half-vortex cores in polariton condensates using spin interactions and TE-TM splitting.

## Key findings

- Half-vortices can spontaneously form and remain stable in microcavity polariton condensates.
- All-optical switching of vortex core polarization is achievable through cross-spin interactions.
- The switching mechanism is observable via polarization-resolved intensity measurements.

## Abstract

Vortices are topological objects carrying quantized orbital angular momentum and have been widely studied in many physical systems for their applicability in information storage and processing. In systems with spin degree of freedom the elementary excitations are so called half-vortices, carrying a quantum rotation only in one of the two spin components. We study the spontaneous formation and stability of localized such half-vortices in semiconductor microcavity polariton condensates, non-resonantly excited by a linearly polarized ring-shaped pump. The TE-TM splitting of optical modes in the microcavity system leads to an effective spin-orbit coupling, resulting in solutions with discrete rotational symmetry. The cross-interaction between different spin components provides an efficient method to realize all-optical half-vortex core switching inverting its circular polarization state. This switching can be directly measured in the polarization resolved intensity in the vortex core region and it can also be applied to higher order half-vortex states.