Light propagation in tunable exciton-polariton one-dimensional photonic   crystals
  Simulations of propagation of light beams in specially designed multilayer semiconductor structures (one-dimensional photonic crystals) with embedded quantum wells reveal characteristic optical properties of resonant hyperbolic metamaterials. A strong dependence of the refraction angle and the optical beam spread on the exciton radiative lifetime is revealed. We demonstrate the strong negative refraction of light and the control of the group velocity of light by an external bias through its effect upon the exciton radiative properties. 
E. S. Sedov, E. D. Cherotchenko, S. M. Arakelian, and A. V. Kavokin
cond-mat.mes-hall physics.optics