Switchable dual-band to broadband terahertz metamaterial absorber incorporating a VO<sub>2</sub> phase transition
Tingting Lv, Guohua Dong, Chunhua Qin, Jia Qu, Bo Lv, Wenjia Li, Zheng Zhu, Yuxiang Li, Chunying Guan, Jinhui Shi
Abstract
We design and demonstrate a thermally switchable terahertz metamaterial absorber consisting of an array of orthogonal coupled split-ring metal resonators involving a VO 2 phase transition. Numerical results indicate that the active metamaterial always absorbs the TE wave in dual-band regardless of insulating and metallic VO 2 , while the insulator-to-metal phase transition enables a switchable effect between dual-band and broadband absorption of the TM wave with the resonant frequency tunability of 33%. Especially under the metallic VO 2 state, the absorption properties are polarization-dependent and exhibit a switching effect between dual-band and broadband absorption with the increase of the polarization angle. The tunable absorption mechanism can be explained by effective impedance theory and electric energy density distributions. The proposed dual-band to broadband metamaterial switching absorber may have broad applications in sensors, imaging and emitters.