Optical Spin Hall Effect Pattern Switching in Polariton Condensates in Organic Single-Crystal Microbelts.

Topological polaritons, combining the robustness of the topologically protected edge states against defects and disorder with the strong nonlinear properties of polariton bosons, represent an excellent platform to investigate novel photonic topological phases. We demonstrate the optical spin Hall effect (OSHE) and its symmetry switching in the exciton-polariton regime of pure DPAVBi crystals. Benefiting from the photonic Rashba-Dresselhaus spin-orbit coupling, we observe the separation of left- and right-circularly polarized emission in momentum space and real space, a signature of the OSHE. Above the lasing threshold, the OSHE pattern changes due to transverse quantization in the microbelt. This simple device has great potential applications in topological polaritons, such as information transmission, photonic integrated chips, and quantum information.