基于二氧化钒宽、窄带可切换的双功能超材料吸收器研究

Wide and narrow band switchable bi-functional metamaterial absorber based on vanadium dioxide

本文提出了一种宽、窄带可切换的双功能超材料吸收器。在超材料吸收器的结构中,引入了相变材料二氧化钒(VO_(2)),仅利用单个可切换超表面就能实现不同的功能,其不同功能之间的相互转换通过VO_(2)绝缘态和金属态之间的可逆相变特性实现。当VO_(2)处于金属态时,设计的结构可以看作一个超材料宽带吸收器。仿真结果表明,在1.55THz至2.21THz的宽带频率范围内,吸收率超过98%。当VO_(2)处于绝缘态时,该结构作为窄带吸收器,在共振频率2.54THz、2.93THz和3.34THz处的吸收率在95%以上,实现了完美吸收。此外,还讨论了几何参数对超材料吸收器吸收率性能的影响。由于单元结构的对称性,该吸收器在电磁波垂直入射时具有极化不敏感特性,并且在大入射角范围内仍能保持良好的吸收性能。因此,本文提出的可切换双功能超材料吸收器可广泛应用于太赫兹调制、热发射器和电磁能量采集等各种领域。

A wide-band and narrow-band switchable bi-functional metamaterial absorber is presented in this paper.The phase change material vanadium dioxide(VO_(2))is introduced in the structure of the metamaterial absorber,and different functions can be achieved by using only a single switchable metasurface.The mutual conversion of different functions is realized by the reversible phase transition between the VO_(2)insulating state and the metal state.When VO_(2)is in metallic state,the designed structure can be regarded as a metama-terial wide-band absorber.The simulation results show that the absorption is over 98%in the frequency range of 1.55 THz to 2.21 THz.When VO_(2)is in the insulating state,the structure acts as a narrow-band absorber,and the absorption at resonance frequencies of 2.54,2.93 and 3.34 THz is over 95%.In addition,the effect of geometric parameters on the absorption of metamaterial absorber is discussed.Because of the symmetry of the element structure,the absorber is insensitive to the polarization when the electromagnetic wave is vertic-ally incident,and it can keep good absorption performance with the large incident angle.Therefore,the switchable bi-functional metamaterial absorber proposed in this paper can be widely used in terahertz modulation,thermal emitters and electromagnetic energy acquisition,etc.