  We show that polaritons in an array of interacting micro-cavities with strong
atom-photon coupling can form a two-component Bose-Hubbard model. Both
polariton species are thereby protected against spontaneous emission as their
atomic part is stored in two ground states of the atoms. The parameters of the
effective model can be tuned via the driving strength of external lasers. We
also describe a method to measure the number statistics in one cavity for each
polariton species independently.
