Tunable defect mode realized by graphene-based photonic crystal

•A novel PhC embedded with grapheme sheets is presented, tunable defect is realized.•The mechanism of the tunable defect is explained using the change of equivalent thickness.•The electromagnetic force of a slab is calculated, which indicates the structure can serve as a tunable force generator.

In this literature, we propose an active terahertz 1D photonic crystal, which consists of silicon layers and air layers. A graphene sheet is embedded at the interface between dielectric and air. Tunable photonic band gap is realized by changing the Fermi level of graphene. Transmission Matrix Method is utilized to explain the influence of the graphene layer. We also demonstrate that a dielectric slab attached with a thin sheet made of single-negative metamaterial acts like a pure dielectric slab with a thinner thickness. A tunable blue shift of the band gap can be realized by simply applying different chemical potentials on the graphene sheet. This feature can be utilized for the design of tunable high-gain antenna array and force generator in terahertz band.