Coherent Exciton-Trion-Polaritons in 2D Materials: Highly Correlated States of Matter and Light*

Exciton-trion-polaritons are robust coherent hybrid excitations involving excitons, trions, and photons ^[1]. In these polaritons, the 2-body exciton states are coupled to the material ground state via exciton-photon interaction and the 4-body trion states are coupled to the exciton states via Coulomb interaction. The 4-body trion states are not directly optically coupled to the material ground state ^[2]. The energy-momentum dispersion of these polaritons exhibit three bands. We realized these polaritons by coupling a doped monolayer of 2D-MoSe₂ with a 1D photonic crystal waveguide. Strong coupling between the excitons, trions, and photons was observed in the energy-band dispersion obtained via reflectivity and photoluminescence measurements. Three Rabi-split positive-mass-dispersion polariton bands were observed. Our theoretical model [1] describing exciton-trion-polaritons matches our experimental results with remarkable accuracy. [1] arXiv:2009.13069. [2] Phys. Rev. B 102, 085304 (2020).