Thermo-optic modulator based on vanadium dioxide and nonlinear Kerr medium in terahertz region

Three-layer design of multi-functional terahertz (THz) metamaterials is proposed and numerically investigated, where the nonlinear Kerr-media is sandwiched between the phase change material of vanadium dioxide (VO2). Owing to the unique picosecond response of VO2 at different temperature, a high transmission is achieved before the phase transformation. When the vanadium dioxide is in the metallic phase, three band perfect absorption exist in the MIM structure. To fully dig out such high absorption, the impedance matching and effective medium theory are taken to obtain the effective dielectric and permeability. The underlying physical mechanism is further investigated with the normalized electric and magnetic field distribution at each resonant peak. In addition, a switcher is realized when the external pump light is utilized to irradiate nonlinear Kerr-media and its high sensing capability is explored with different Kerr medium. Therefore, our dynamic tunable modulator paves a new way in the design of tunable THz modulators, sensors and switchers.

Automated summary

A three-layer design of multi-functional terahertz metamaterials is proposed and investigated, utilizing the nonlinear Kerr-media sandwiched between a phase change material of vanadium dioxide. The design achieves high transmission before phase transformation and exhibits three band perfect absorption in the metallic phase of vanadium dioxide. Impedance matching and effective medium theory are used to extract high absorption. The physical mechanism is further studied through analysis of the normalized electric and magnetic field distribution. Additionally, a switcher is realized by irradiating the nonlinear Kerr-media with external pump light, and its sensing capability with different Kerr medium is explored.