Interacting Dark Resonances: Interference Effects Induced by Coherently   Altered Quantum Superpositions
  We predict the possibility of sharp, high-contrast resonances in the optical response of a broad class of systems, wherein interference effects are generated by coherent perturbation or interaction of dark states. The properties of these resonances can be manipulated to design a desired atomic response. 
M. D. Lukin, S. F. Yelin, M. Fleischhauer, and M. O. Scully