Dual-band, polarization-insensitive metamaterial perfect absorber based on monolayer graphene in the mid-infrared range

A dual-band, polarization-insensitive metamaterials (MMs) perfect absorber based on monolayer graphene in the mid-infrared range were designed and researched. By designing a simple structure, under the optimal geometric parameters of the proposed structure, we simulate a MMs perfect absorber, corresponding the two absorption peaks at wavelengths 48.49 μm and 65.33 μm with absorptivity 99.31% and 99.91%. Physical mechanisms of the MMs perfect absorber is investigated by the impedance matching theory. The study found that by changing the Fermi level of graphene, the resonant peak wavelength of the proposed MMs perfect absorber can be flexibly tuned without re-manufacturing the structure. In addition, the research results also indicate that the presented MMs perfect absorber has greater tolerance to the incident angle of the transverse magnetic (TM) and transverse electric (TE) modes, where the polarization is insensitive. This research can be used for based on graphene in the mid-infrared range photonic devices in absorption, imaging, detection, filtering and other applications.