Fig. -c present time-dependent polariton eigenenergies that fluctuate due to the evolution of phonons (in the mixed-quantum classical picture). In Fig. the photon frequency is much lower (off-resonant) than the molecular excitation. As a result, there is no substantial population transfer from the upper polaritons and the dark states (both of which are primarily excitonic) to the lower polariton (primarily photonic). As a consequence of this, the lower polariton, despite having a large photonic character, does not show up in the PL spectra since it does not get populated. At the same time even though the upper polariton and the dark states are substantially populated, they appear dark in the PL spectra due to negligible photonic character.