The formation of Rabi splitting/polariton states comes from a collective phenomenon, resulting in the well-known dependence of √ 𝑁 or equivalently √︀ 𝑁/𝒱 for Ω R , which has been experimentally confirmed . It has been estimated that there are 𝑁 ∼ 10 6 -10 12 molecules effectively coupled to the cavity mode for recent VSC experiments , and Ω R ∼ 100 cm -1 when 𝜔 0 ≈ 1000 cm -1 for typical VSC experiments . Despite encouraging progress, what remains largely a mystery is how the collective lightmatter coupling can induce the VSC modified rate constant . Another less investigated area is why forming polaritons at a finite incident angle does not necessarily lead to the change of the VSC kinetics, and the only observed VSC effects occur at 𝑘 ‖ = 0 (or 𝜃 = 0).