Fig. 3. Trion-polariton nonlinearity.

We consider large cavity–exciton detuning δ_C–X = −15.4 meV. a Spectra of the MPB and LPB for the excitation power from 5 to 50 nW (power increases from bottom to top). The MPB and LPB peaks are fitted with Gaussians. The fitting of the exciton-like LPB peak (lower energy peak) is performed for the first 4 powers, since it becomes broad and weak at higher densities and the fitting procedure is not reliable. b Extracted peak positions of the MPB mode vs estimated total exciton-trion density. c Trion-polariton Rabi-splitting vs exciton-trion density. Red solid curves in b, c correspond to the theoretical modelling results. The error bars [95% confidence interval (CI)] are estimated taking into account the random error in determination of the peak positions in a as well as possible systematic error (ΔΩ_T ~ 0.5 meV) due to the uncertainty of the fitting parameters in the coupled oscillators model.