Metamaterial absorbers can achieve high-efficiency electromagnetic absorption in a specific band, which have been used in biochemical sensing, photoelectric detection, imaging and other fields. Tunable metamaterial absorbers provide more possibilities for the development of multifunctional electromagnetic absorption devices. Here we propose a tunable and polarization-dependent terahertz metamaterial absorber which can work for both linearly and circularly polarized waves. By introducing single layer graphene and vanadium dioxide (VO₂), switching between the two working states and wide-range tuning of the absorption efficiency are realized. When VO₂ is in insulating state, the absorber shows different tunable absorption performance for the x- or y-polarized terahertz waves, in which the maximum absorption rate is close to 100%. When VO₂ is in metallic state, the metasurface behaves as a chiral absorber, and the maximum absorption difference between the two circular polarizations is about 0.45, while the tuning efficiency reaches 86.3%. Under the two working conditions, the absorber can maintain efficient absorption with a large incident angle. In addition, as an application exploration of the absorber, we demonstrated its application in tunable and polarization multiplexed near-field image display.

中文翻译：

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基于各向异性超表面的太赫兹波的偏振依赖性和可调谐吸收

超材料吸收器可以在特定频带中实现高效电磁吸收，已被用于生化传感，光电检测，成像和其他领域。可调节的超材料吸收器为多功能电磁吸收装置的开发提供了更多的可能性。在这里，我们提出了一种可调谐且与偏振有关的太赫兹超材料吸收器，该吸收器可用于线性和圆偏振波。通过引入单层石墨烯和二氧化钒（VO ₂），可以在两种工作状态之间切换并实现吸收效率的宽范围调节。当VO ₂当处于绝缘状态时，吸收器对x或y极化太赫兹波显示出不同的可调吸收性能，其中最大吸收率接近100％。当VO ₂处于金属态时，超颖表面表现为手性吸收剂，两个圆极化之间的最大吸收差约为0.45，而调谐效率达到86.3％。在两种工作条件下，吸收器可以以大入射角保持有效吸收。另外，作为吸收体的应用探索，我们展示了其在可调谐和偏振复用近场图像显示中的应用。