We design an actively tunable polarization-sensitive multiband absorber in the mid-infrared region, which consists of stacked graphene multilayers separated by dielectric layers on a metal mirror. Benefiting from the anisotropic structure, the absorber has dual absorption bands with almost perfect absorption at different wavelengths under the x and y polarizations. Analyzing the electric field amplitude distributions and the surface currents, we find that the absorption peaks under the same polarization are excited in the graphene layers independently. Therefore, more absorption bands can be achieved by increasing the graphene layers. Adjusting the Fermi energy of the graphene layers, the working wavelengths of the polarization-sensitive multiband absorbers can be tuned actively, and thus achieving a wide band regulation range. Besides, the peak number and the peak strength of the multiband absorber can be actively controlled by the polarization angle as well. We also propose a method to design an actively tunable polarization-sensitive multiband absorber, which may have potential applications in mid-infrared devices, such as polarization-sensitive filters and detectors.

我们在中红外区域设计了一种主动可调的偏振敏感多波段吸收器，它由堆叠的石墨烯多层组成，由金属镜上的介电层隔开。受益于各向异性结构，吸收体具有双吸收带，在x和y下的不同波长处具有几乎完美的吸收极化。分析电场幅度分布和表面电流，我们发现在相同极化下的吸收峰在石墨烯层中独立地被激发。因此，可以通过增加石墨烯层来实现更多的吸收带。通过调节石墨烯层的费米能量，可以主动调节偏振敏感多波段吸收体的工作波长，从而实现宽波段调节范围。此外，多波段吸收体的峰值数量和峰值强度也可以通过偏振角来主动控制。我们还提出了一种设计主动可调偏振敏感多波段吸收器的方法，该吸收器可能在中红外设备中具有潜在应用，例如偏振敏感滤光片和检测器。