A strong-coupled system of photonic and electronic polar excitations becomes a mixture of the two, bending the relations of their time and space oscillations, spanning them from those of the light and fast moving one to the heavy and slow counterpart. Two main oscillation frequencies will be present at each given space frequency, the new normal modes. Their symultaneous excitation by the ultrafast laser pulse gives rise to a beating in the time domain, which is equivalent to an oscillating energy transfer between the photon and exciton field. In the side, a space-time chart cut along the diameter of a polariton fluid, illustrates the state-of-the art imaging of sub-ps Rabi oscillations resonantly excited by a 100 fs laser pulse on a very good quality sample, together with the central depletion due to polaritonic repulsions and the subsequent re-excitation by an eco pulse.
Ultrafast Control and Rabi Oscillations of Polaritons, Phys. Rev. Lett. 113, 226401 (2014)