The light-matter coupling term, ∝ ∑︀ k,𝑗 qk ⊗ 𝜇( R𝑗 ) in Eq. 1, will hybridize the bright state and the photon-dressed ground states, generating the polariton states . When all dipoles are fully aligned, such that cos 𝜙 𝑗 = 1, and under the resonance condition 𝜔 k (𝑘 ‖ ) = 𝜔 0 , the light-matter hybridization generates the upper and lower polariton states (which are lightmatter-entangled states) as