Optical response of photonic crystal heterjunction structure with a nonlinear defect

In order to optical response in nonlinear material,considering the general problem of electronmagnetic wave propagation through one-dimensional photonic crystal heterjunction structure with a nonlinear defect,an expression for the optical response of such dielectric superlattice is obtained when the nonlinear impurity dielectric constant is in δ function approximation.The simulation results show that once the nonlinear medium sandwiched between two photonic crystals and the system exhibits bistability and multistability.Then the conditions for the onset of bistability and multistability are discussed.Comparison proves the δ function approximation and the nonlinear layer of finite width displays qualitatively similar behavior,which might supply a beneficial reference for the design zero threshold laser and nonlinear optical elements.