Nonlinear response in a multilayer system of Lorentz type single-negative metamaterial

We explore the nonlinear response in a multilayer system of Lorentz type single negative metamaterials by inserting a nonlinear layer into a symmetric periodic structure with alternating epsilon-negative (ENG) and mu-negative (MNG) materials. A pass band with flat-top is observed and concentrated at a fixed central frequency regardless of the change of other parameters of the multilayer system. Meanwhile the electric field distribution and bistability at the central frequency are also studied.