Fig. presents the purely absorptive 2DES polariton spectra (see Sec. IV) of a monomer coupled to a singlemode cavity. Fig. represents the polariton 2DES spectra with various cavity loss rates Γ and with a fixed coupling strength of g c = 57 meV. Fig. presents the polariton 2DES spectra with various coupling strengths g c at a fixed cavity loss rate of Γ = 10 meV. For all 2DES plots, the horizontal and vertical dotted lines indicate the polariton peak locations ±g c along the emission and excitation axes. Note that the actual peak position will be shifted with different cavity loss rates, as indicated by Eq. 57 and Fig. .