基于二氧化钒相变的可调谐超材料吸收器设计

Design of Adjustable Metamaterial Absorber Based on the Phase Transition of Vanadium Dioxide

本文基于二氧化钒(VO_(2))独特的相变性质,设计了一种带宽可调谐的多层超材料吸收器。吸收器由VO_(2)方形环表面、聚酰亚胺(Polyimide)介质层、VO_(2)薄膜层、十字形金(Au)层、聚酰亚胺介质层和金薄膜层构成。当VO_(2)处于金属态时,结构可作为宽带吸收器,仿真结果表明在2.3 THz与5.3 THz之间吸收率超过90%,且吸收性能对入射光偏振不敏感,入射角度的改变对吸收性能影响较小。而当VO_(2)处于绝缘态时,结构可作为窄带吸收器,仿真结果表明在7.1 THz处吸收率超过99%,达到完美吸收效果,此时同样对入射光偏振不敏感。此外,VO_(2)处于绝缘态时,吸收器结构具有良好的传感性能,可拓展应用于成像、检测和传感等领域。

In recent years, terahertz technology has received more and more attention and has made great progress. With the development of terahertz technology and metamaterial, adjustable metamaterial absorbers applied to the terahertz band have good application prospects. Vanadium dioxide(VO_(2)) is a typical reversible phase change material. It is insulative at room temperature and changes to be metallic when the temperature reaches 68?C. Based on the unique properties of vanadium dioxide(VO_(2)) in terms of phase change, a multi-layer metamaterial absorber with switchable absorption properties is proposed. The absorber is constituted by six layers, from the top layer to the bottom layer are vanadium dioxide(VO_(2)) square ring, polyimide(PI) dielectric layer, vanadium dioxide(VO_(2)) film layer, cross-shaped gold layer, polyimide(PI) dielectric layer, and gold film layer. When vanadium dioxide(VO_(2)) is at the metallic state, the structure can be used as a broadband absorber. The simulation results show that the absorptance exceeds 90% between 2.3 THz and 5.3 THz, which is not sensitive to the polarization of the incident light,and the change of the incident angle has little effect on the absorption performance. When vanadium dioxide(VO_(2)) is at insulating state, the structure can be used as a narrow-band absorber. The simulation results show that the absorptance exceeds 99% at 7.1THz, achieving a perfect absorption effect, which is not sensitive to the polarization of the incident light as well. Therefore, by switching the different states of vanadium dioxide(VO_(2)), the switching of the different absorption properties of the metamaterial absorber is realized. Moreover, it is explored that the structure has good sensing performance when vanadium dioxide(VO_(2)) is in an insulating state and the sensing sensitivity of the structure is 200 GHz/RIU. The absorber has the advantages of switchable absorption performance between narrowband and broadband, and multifunctional application. The structure can play an important role in terahertz imaging, detection, communication and sensing, and other emerging terahertz fields.