Lv Tingting, Dong Guohua, Qin Chunhua, Qu Jia, Lv Bo, Li Wenjia, Zhu Zheng, Li Yuxiang, Guan Chunying, Shi Jinhui
Opt Express. 2021 Feb 15;29(4):5437-5447. doi: 10.1364/OE.418020.
We design and demonstrate a thermally switchable terahertz metamaterial absorber consisting of an array of orthogonal coupled split-ring metal resonators involving a VO phase transition. Numerical results indicate that the active metamaterial always absorbs the TE wave in dual-band regardless of insulating and metallic VO, 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 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.
我们设计并展示了一种热可切换太赫兹超材料吸收器，它由一系列涉及VO相变的正交耦合裂环金属谐振器阵列组成。数值结果表明，无论VO处于绝缘态还是金属态，有源超材料总是在双波段吸收TE波，而绝缘体到金属的相变能够在TM波的双波段和宽带吸收之间实现可切换效应，谐振频率可调谐性为33%。特别是在金属VO状态下，吸收特性与偏振有关，并且随着偏振角的增加，在双波段和宽带吸收之间呈现出切换效应。可调谐吸收机制可以通过有效阻抗理论和电能密度分布来解释。所提出的双波段到宽带超材料切换吸收器可能在传感器、成像和发射器等方面有广泛应用。
