such that the coupling strength between the upper polariton and the acceptor increases as √ N . This is in stark contrast to the case when only individual pairs of donor and acceptor molecules are coupled and the coupling strength scales as 1/ √ N (see Eq. 212a). Additionally, the effective reorganization energy in the large Rabi splitting regime between the upper polariton and the acceptor is λ +A = N λ thus the reorganization energy of the polariton states scales as N . The rate constant at resonance is thus