Polarization-dependent and tunable absorption of terahertz waves based on anisotropic metasurfaces

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. Minable 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. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Automated summary

A tunable and polarization-dependent terahertz metamaterial absorber is proposed, which can work for both linearly and circularly polarized waves, and achieve high absorption efficiency with wide-range tuning. The absorber demonstrates different tunable absorption performances for x- or y-polarized terahertz waves when VO2 is in insulating state, and behaves as a chiral absorber when VO2 is in metallic state. Efficient absorption is maintained with a large incident angle under the two working conditions. Additionally, the absorber is applied in tunable and polarization multiplexed near-field image display.