Polariton lasing in nonresonantly driven coupled planar microcavities

Multi-level exciton-polariton systems offer an attractive platform for studies of nonlinear phenomena resulting from the strong light-matter interaction. We demonstrate Bose-Einstein condensation of polaritons and dual-wavelength polariton lasing in a non-resonantly driven, vertically coupled microcavities. Time-resolved measurements reveal the complex dynamics of the processes responsible for the excitation transfer between the exciton reservoir and polariton levels. In particular, we observe that condensates at polariton branches do not form simultaneously following the excitation pulse. Moreover, we find that the presence of the condensate triggers energy-degenerate parametric oscillation, so far observed only under resonant excitation. Non-resonant excitation enables a clean observation of the scattering effects thanks to a spectral separation of the excitation and measured signal. Our findings, described by open-dissipative Gross-Pitaevskii equation coupled to reservoir rate equations, offer an insight into the factors governing dynamics of polaritons in a multi-level system. The inherent tunability of our platform is promising for the realization of photonic devices, such as polariton-based logic gates and constructing polariton lattices enabling two-dimensional hopping.