ABSTRACT

We design and simulate a tunable dual-band perfect absorber. This absorber is composed of a circular graphene layer with an ellipse cut out in the centre, separated by a dielectric layer in the middle and a gold mirror at the bottom. Results reveal that there exist two perfect absorption peaks in the terahertz band. The position of the absorption peak can be changed by adjusting the Fermi level and geometric parameters of the graphene pattern. Furthermore, the absorber is insensitive to the polarized incident light with a wide incident angle. Functionalities are achieved based on a simple and symmetrical single-layer graphene pattern, which can greatly reduce the manufacturing costs. The proposed absorber can be applied in the field of graphene-based photonic devices, such as detectors, sensors, and filters.

摘要

我们设计并仿真了一个可调双频完美吸收器。该吸收器由一个圆形的石墨烯层组成，该层的中心有一个椭圆形的切口，中间被一个介电层隔开，底部被一个金镜隔开。结果表明，在太赫兹带中存在两个完美的吸收峰。吸收峰的位置可以通过调整费米能级和石墨烯图案的几何参数来改变。此外，吸收器对具有宽入射角的偏振入射光不敏感。基于简单且对称的单层石墨烯图案实现功能，可以大大降低制造成本。提出的吸收器可应用于基于石墨烯的光子器件领域，例如探测器，传感器和滤波器。