Takemura, N.Anderson, M. D.Biswas, S.Navadeh-Toupchi, M.Oberli, D. Y.Portella-Oberli, M. T.Deveaud, B.2017-01-242017-01-242017-01-24201610.1103/PhysRevB.94.195301https://infoscience.epfl.ch/handle/20.500.14299/133664WOS:000386769400004The interaction between coherent polaritons and incoherent excitons plays an important role in polariton physics. Using resonant pump-probe spectroscopy with selective excitation of single polariton branches, we investigate the different dephasing mechanisms responsible for generating a long-lived exciton reservoir. As expected, pumping the upper polariton results in a strong dephasing process that leads to the generation of a long lived reservoir. Unexpectedly, we observe an efficient reservoir creation while exciting only the lower polariton branch when the detuning is increased towards positive detuning. We propose a simple theoretical model, the polaritonic Bloch equations, to describe the dynamics of the system.text::journal::journal article::research article