Excitation of localized condensates in the flat band of the exciton-polariton Lieb lattice

We propose a way to directly excite compact localized condensates in a nearly flat band of the exciton- polariton Lieb lattice by short Laguerre-Gaussian pulses and investigate the dynamics of these condensates in the presence of repulsive polariton-polariton interactions and distributed losses in the lattice. The evolution of a low-density compact polariton condensate shows fast Rabi oscillations between its excitonic and photonic components, with slow beatings of the Rabi oscillation amplitude. At higher polariton densities the Rabi oscillations are still present, but their beatings are smeared out due to the polariton-polariton repulsion and distributed losses in the lattice. We further show that an incoherent background pumping can be used to increase the lifetime and stability of compact localized states. ©2018 American Physical Societ