  We propose a practical scheme to observe the polaritonic quantum phase
transition (QPT) from the superfluid (SF) to Bose-glass (BG) to Mott-insulator
(MI) states. The system consists of a two-dimensional array of photonic crystal
microcavities doped with substitutional donor/acceptor impurities. Using
realistic parameters, we show that such strongly correlated polaritonic systems
can be constructed using the state-of-art semiconductor technology.
