Electrically tunable optical bistability based on one-dimensional photonic crystals with nonlinear nanocomposite materials.

A one-dimensional photonic crystal structure with a nonlinear metal-dielectric nanocomposite defect layer is proposed to control the optical bistability (OB) of the transmitted wave by tuning the externally applied dc electric field. Using the transfer matrix method for dielectric layers and solving the Helmholtz nonlinear equation in the nonlinear composite layer, the linear transmittance spectrum and the nonlinear transmission curve are illustrated graphically for different applied fields. A field-dependent defect mode is observed in the linear transmittance spectrum. Consequently, the OB switch-up and -down thresholds can be manipulated via the applied field intensity. Due to the field dependence of composite layer refractive index, the physical response of the observation is the dynamical shifting of the defect mode. Moreover, it is shown that the volume fraction, shape, and type of the embedded nanoparticles as well as the kind of the dielectric host have large influences on the OB threshold. The proposed structure has significant potential applications in optical integrated devices. [ABSTRACT FROM AUTHOR]