Strong coupling between light and matter generates hybrid polaritons. We
present a continuum model that describes the polaritons by light and matter
densities of states (DOS) that only depend on the refractive index of the
material. This model is applied to molecular polaritons derived from molecules
with broad spectral absorption. While the photonic DOS has a complex spectral
distribution, the matter DOS is largely unmodified by strong coupling. We argue
that bright states cannot be partitioned from dark states, and instead the
photonic DOS is shared over a vast number of matter states