Ultrafast intermode parametric scattering dynamics in room-temperature polariton condensates

Parametric scattering dynamics are general and of crucial importance for cavity exciton polaritons. Here, parametric scattering process driven by exciton polariton condensates has been revealed in a 1D ZnO microcavity between the whispering-gallery mode and quasiwhispering-gallery mode. When the occupation of the produced polariton condensate is dense enough, polariton condensates formed on quasiwhispering-gallery mode can be scattered towards the ground state of the adjacent whispering-gallery modes at higher and lower energies. By using the femtosecond angle-resolved spectroscopic imaging technique, the ultrafast dynamics of this intermode polariton parametric scattering have been explicitly observed. The scattering towards a higher mode occurs faster than that to a lower-energy mode by less than a picosecond. The revealed dynamics can not only expand the present investigations on polariton parametric scattering, but also promote the potential applications in, e.g., quantum information processing.