Dark propagation modes in optical lattices
  We examine the stimulated light scattering onto the propagation modes of a dissipative optical lattice. We show that two different pump-probe configurations may lead to the excitation, via different mechanisms, of the same mode. We found that in one configuration the scattering on the propagation mode results in a resonance in the probe transmission spectrum while in the other configuration no modification of the scattering spectrum occurs, i.e. the mode is dark. A theoretical explanation of this behaviour is provided. 
Michele Schiavoni, Laurent Sanchez-Palencia, Francois-Regis Carminati,   Ferruccio Renzoni, Gilbert Grynberg