Switchable dual-band to broadband terahertz metamaterial absorber incorporating a VO2 phase transition

We design and demonstrate a thermally switchable terahertz metamaterial absorber consisting of an array of orthogonal coupled split-ring metal resonators involving a VO2 phase transition. Numerical results indicate that the active metamaterial always absorbs the TE wave in dual-band regardless of insulating and metallic VO2, 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 VO2 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. (c) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Automated summary

The article presents a thermally switchable terahertz metamaterial absorber based on VO2 phase transition, capable of switching absorption effects in different frequency bands, with polarization-dependency and absorption switching effects under metallic VO2 state at different polarization angles.