Dual-Wavelength Exciton-Polariton Condensation via Relaxation of Multiple Vibrational Quanta in Organic Microcavities

The relaxation of organic polaritons is a key aspect for understanding nonequilibrium bosonic condensation in organic microcavities. In this work, dual-branch vibrational quanta-assisted polariton condensation is experimentally observed in organic single-crystal-filled microcavities. By precisely modulating the thickness of the planar optical resonator, we can tune the ground states of two lower polariton branches to perfectly match the energies of two vibrational modes and consequently trigger polariton condensation in both branches. These condensates have nearly identical thresholds. Dynamical analysis indicates that efficient energy relaxation of the photogenerated excitons to the two vibrational modes through the nonradiation of two separately vibrational quanta enables polaritons to populate the ground states of these two lower polariton branches. Our work is evidence of the importance of the vibrational quanta relaxation mechanism for polariton condensation and provides a pathway for multicolor polariton condensation and future laser displays.