Multi-band and high-sensitivity perfect absorber based on monolayer graphene metamaterial

• Published in: Diamond and related materials 2021-01, Vol.111, p.108227, Article 108227
• Main Authors: Jiang, Liying, Yuan, Chuang, Li, Zhiyou, Su, Ju, Yi, Zao, Yao, Weitang, Wu, Pinghui, Liu, Zhimin, Cheng, Shubo, Pan, Miao
• Format: Article
• Language: English
• Subjects: Absorbers; Absorption; Coupled modes; Coupling; Critical coupling; Environmental monitoring; Finite difference time domain method; Graphene; Impedance matching; Metamaterial; Metamaterials; Modulators; Monolayers; Near infrared; Optoelectronic devices; Perfect absorption; Phase matching; Resonance; Sensitivity; Sensors; Time domain analysis
• ISSN: 0925-9635; 1879-0062
• DOI: 10.1016/j.diamond.2020.108227

The Finite Difference Time Domain (FDTD) method is used for the simulation, and a new method based on critical coupling and guided resonance is proposed theoretically and numerically to realize a multi-band ideal absorber (PA) of monolayer graphene. Its physical mechanism can be more perfectly analyzed through impedance matching and coupled mode theory (CMT). Due to the guided resonance (100% transmission or reflection efficiency is obtained through the coupling of the leakage mode and the guided mode under the phase matching condition), the perfect absorber can obtain four perfect absorption peaks. The resonance wavelengths are located at λ1 = 1085.03 nm, λ2 = 1131.48 nm, λ3 = 1187 nm and λ4 = 1365.35 nm, respectively. Their absorption rates are 95.88%, 99.81%, 97.44% and 95.30%. At the same time, we can also see a phenomenon in which the spectral position and value of the absorption peak can be adjusted by changing the relevant geometric parameters in the system (the geometric size, period, and incident angle of the hexagonal air hole absorber). Meanwhile, the structure we designed has certain advantages in the field of similar absorber research by briefly calculating related values of sensing performance. The sensitivity of its four resonance peaks are 46.45, 94.35, 151 and 598.9 nm/RIU, and FOM are 5.445, 11.192, 19.895 and 85.680. So we believe that the research has huge application prospects in terms of sensors, tunable spectrum detection, environmental monitoring and medical diagnosis, modulators and optoelectronic device sensors. [Display omitted] •The intensity and wavelength range of the absorption spectrum can be adjusted by changing the geometric parameters.•We get four perfect absorption peaks about monolayer graphene.•The sensitivity of this model is higher than that of other similar models.•The absorber has good operating angular polarization tolerance at the incidence angle.