Fig. 4.

Tunable parameters in the effective Hamiltonian. Dependence of the parameters in the effective polariton Hamiltonian (Eq. (9)) on the inverse cavity height. The blue dashed line shows the variation of the group velocity $\overline{v}$ which changes sign at the critical cavity height L_c, leading to the inversion of chirality. The orange dot-dashed line shows the variation of the trigonal warping parameter $\overline{t}$ which becomes dominant close to criticality. These parameters have been normalized to v = 3Ωa/2 and t = 3Ωa²/8 which are the group velocity and trigonal warping parameters, respectively, in the absence of image dipoles and light–matter interactions. The orange dot-dashed line in the inset shows the variation of the CDP frequency ${\overline{\omega }}_0$, while the blue dashed line in the inset shows the variation of the wavevector-dependent diagonal term D. Plots obtained with ${\omega }_{\mathbf{K}\mathrm{0}}^{\mathrm{ph}}=2.5{\omega }_0$ and Ω = 0.01ω₀