Tailoring MoS 2 Exciton-Plasmon Interaction by Optical Spin-Orbit Coupling.

Molybdenum disulfide (MoS ₂ ) monolayer as one of the atomic thickness two-dimensional materials has remarkable electronic and optical properties, which is an ideal candidate for a wide range of optoelectronic applications. However, the atomic monolayer thickness poses a significant challenge in MoS ₂ photoluminescence emission due to weak light-matter interaction. Here, we investigate the MoS ₂ exciton-plasmon interaction with spin-orbit coupling of light. The plasmonic spiral rings with subwavelength dimensions are designed and fabricated on hybrid substrates. MoS ₂ photoluminescence enhancement can be actively controlled by changing the incident optical spin states, laser powers, and the nanospiral geometries, which is arising from the change of field enhancement at near-field region. Planar light-emitting devices based on spin-orbit coupling (SOC) effect were further realized and flexibly controlled by changing the polarization of light. The SOC effect is discussed by the accumulation of geometric and dynamic phases, which can be demonstrated and elaborated by the Majorana sphere model. Our results provide a way to manipulate MoS ₂ light-matter interaction actively and can be further applied in the spin-dependent light-emitting devices at the nanoscale.