Spaser chains
  We show that depending on the values of the coupling constants, two different scenarios for the stationary behavior of a chain of interacting spasers may be realized: (1) all the spasers are synchronized and oscillate with a unique phase and (2) a nonlinear autowave travels along the chain. In the latter scenario, the traveling wave is harmonic unlike excitations in other known nonlinear systems. The amplitude of this wave is determined by pumping and the wavenumber is determined by the coupling constants. Due to the nonlinear nature of the system, any initial distribution of spasers' states evolves into one of these steady states. 
E. S. Andrianov, A. A. Pukhov, A. V. Dorofeenko, A. P. Vinogradov, and   A. A. Lisyansky
cond-mat.mes-hall