Ultra-slow light pulses in a nonlinear metamaterial
  We find the analytical expression for the threshold intensity necessary to launch ultra-slow light pulses in a metamaterial with simultaneous cubic electric and magnetic nonlinearity. The role played respectively by the permittivity, the permeability, the electric cubic nonlinearity, the magnetic cubic nonlinearity and the pulse duration is clearly identified and discussed. 
Giuseppe D'Aguanno, Nadia Mattiucci and Mark J. Bloemer