Terahertz wave tunable resonator based on compound lattice photonic crystal

A novel terahertz tunable resonator based on the two dimensional silicon photonic crystal of compound lattice is presented. It´s designed to be tunable by making the point defect with optically controlled GaAs, of which the imaginary part of complex refractive index is controlled by external optical field. By applying an external optical field on the point defect, the resonant mode dynamically changes. With the increasing of the imaginary part, the Q value of the resonator decreases. When the mode disappears completely, the cavity can´t resonate. With the combination of waveguide (line defect), we can control the transmission spectrum of this photonic crystal through the tunable resonator. The numerical simulation results show that it has many advantages such as a board band gap, tunability and a small size easy to integrate. It can be used to modulate the on-off state of terahertz wave and fabricate terahertz sources, modulators or switches.