Collective state transitions of exciton-polaritons loaded into a periodic potential
K. Winkler, O.A. Egorov, I.G. Savenko, X. Ma, E. Estrecho, T. Gao, S. Müller, M. Kamp, T.C.H. Liew, E.A. Ostrovskaya, S. Höfling, C. Schneider, Physical Review B 93 (2016).