Multi-band THz plasmonic meta-surface absorber based on dual bias graphene disks: bio sensing application

We propose a Plasmon-induced tunable meta-surface for multiband absorption. It consists of a graphene disk that facilitates perfect absorption; whereas, the dual bias graphene pattern creates an enhanced evanescent wave that facilitates the meta-surface to work as a sensor. The modeling and numerical analysis are carried out using Finite Element Method-based software, CST microwave studio. By exploiting graphene’s tunable properties we demonstrate a multiband super absorption spectrum having a maximum absorption of 99.7% in a frequency range of 0.1–2.0 THz, 6 THz, 9.5 THz, 16 THz, 19.5 THz, and 22.5 THz that also maintain unique optical performance over a wide incidence angle. Further results show sensitivity analysis and comparison of developed equivalent circuit models with full-wave simulation. Also, the total height of the proposed absorber is about 5µm, makes it ultra-thin device with multiple absorption peaks in whole THz spectrum and beyond. Such a high performance wave absorber is in great demand for medical imaging and sensing. Such a robust meta-absorber is an ideal block for several bio sensing applications if the spacer is replaced via any known biological samples.