Bistable absorption in a 1D photonic crystal with a nanocomposite defect layer.

We investigate the nonlinear absorption properties of a defective one-dimensional photonic crystal at the near-infrared range using the nonlinear transfer matrix method. The defect is a nanocomposite layer containing vanadium dioxide nanoparticles sandwiched between two nonlinear dielectric layers. The linear absorption spectrum of the designed structure has three resonant absorption lines at the bandgap region of the photonic crystal. We can reconfigure the structure in the linear regime from nearly transparent to absorbent or vice versa in multiple resonant wavelengths by adjusting the temperature. Moreover, the system shows absorptive bistability by adjusting the intensity and incident angle of the input light. We discuss the tunability of the nonlinear absorption in detail. In the nonlinear regime, we show that, besides the temperature, the structure can be reconfigured from absorbent to transparent and vice versa by adjusting the incident optical power and the incident angle. We validate the results by examining the electric field distribution throughout the structure.

Effect of strain on surface plasmon polaritons of a graphene cladded one-dimensional photonic crystal.

We investigate the dispersion properties of TE-polarized surface plasmon polaritons at the interface of a strained graphene cladded one-dimensional photonic crystal and a homogeneous medium. The optical conductivity of graphene under uniform planar tension is numerically calculated using the perturbation theory and the nearest-neighbor tight-binding approximation. We show that the wavelength, propagation length, and penetration depth of the surface plasmon polaritons in the homogeneous environment and the photonic crystal depend on the magnitude and orientation of the applied strain. Depending on the magnitude and direction of the tension, a Van Hove singularity may appear at the electronic band structure of the graphene in the desired frequency interval. We show that the surface mode corresponding to the Van Hove singularity has the least propagation length. We also observe that strain only affects the penetration depth of the low-frequency surface plasmon polaritons in the homogeneous medium and the high-frequency surface plasmon polaritons in the photonic crystal.

Backward nonlinear surface Tamm states in left-handed metamaterials.

We addressed the existence of the nonlinear electromagnetic surface waves, the so-called Tamm states, that form at an interface separating a nonlinear uniform left-handed metamaterial and a conventional one-dimensional photonic crystal. We found two types of nonlinear surface waves, one with a hump at the interface and the other one with two humps. It was demonstrated that the nonlinear metamaterial can support the both type Tamm states with a backward energy flow and allows for a flexible control of the dispersion properties of surface states. We also, described the intensity-dependent properties of surface Tamm states for a nonlinear self-focusing medium.