Optimal bistable switching in photonic crystals with defect of nonlinear dielectric materials

In this paper, the propagation properties of the electromagnetic (EM) waves in one-dimension photonic crystals (PC) with nonlinear defects layer closed by periodic layered structures are reported. It is shown that in the presence of the nonlinearity, the transmission properties are strongly modulated by both the frequency and intensity, and the system exhibits bistability and multistability. Moreover, we find that both the switching-up and switching-down intensities of the bistable response can be made very low, when the intensity of the incident wave matches the defect mode of the structure. By use of the nonlinear finite-difference time-domain (NFDTD) method, we simulate the bistable threshold of the nonlinear photonic crystals with the kerr medium and the feasibility of making a switch utilizing such a structure. Bistable swithching with a low threshold intensity of 0.0007 kW/cm(2) is obtained. The numerical experiments describe optimal bistable switching in a nonlinear photonic crystal system. A photonic crystal enables the device to operate in single-mode fashion, as if it were effectively one-dimensional. This provides optimal control over the input and output and facilitates further large-scale optical integration.