Thermo-optical and electro-optical tunable dual-band THz absorber based on multi-layer hybrid VO2 phase transition metamaterial

In this paper, a thermo-optical and electro-optical (EO) tunable multifrequency metamaterial THz absorber based on a multi-layer hybrid VO2 transition metamaterial is demonstrated. The reflectivity and transmittivity, and absorptivity of the metamaterial with various geometric parameters are simulated. The simulation results show that the absorptivity reaches 99.4% at an operating frequency of 6.9 THz. The thermo-optical and EO tunable absorption rates are studied by changing the surrounding temperature and bias voltage, respectively. The ab-sorptivity is adjusted from 36.2% to 99.4% and modulation depth is-63.5% when the surrounding temperature rises from 294 to 350 K. The EO wavelength tuning coefficient is-1690.4 pm/V. The effects of geometric pa-rameters on the absorptivity of the metamaterial absorber are also discussed. The impedance matching theory is used to explain the physical mechanism of absorption characteristics. The proposed metamaterial absorber has potential applications including infrared imaging, thermal emitters, electromagnetic shielding and photode-tector, moreover, the research of the thermo-optical and EO tunable absorption characteristics provides a feasible scheme of THz wave modulation and multiplexing.(c) 2021 Optica Publishing Group under the terms of the Optica Publishing Group Open Access Publishing Agreement.