Graphene metasurface for broadband absorption and terahertz sensing

A plasmon-induced terahertz metamaterial absorber is proposed. The bottom ground layer uses gold to block the transmission of terahertz incident waves, and the pattern layer and the ground layer are separated by topas. The 90% absorption bandwidth frequency range of the absorber is 4.6-7.7 THz, and the average absorption rate in this range is 97.6%. Due to the geometric symmetry of the absorber, it has polarization insensitivity. In addition, when the incidence Angle reaches 60 degrees, more than 80% absorption can still be maintained. The numerical simulation shows that the frequency shift of the absorber has a good linear relationship with the change of the refractive index of the proposed absorber, and the sensitivity is 1100 GHz per refractive index unit (GHz/RIU). Therefore, the absorber can be used in more complex electromagnetic scenarios, or as a sensing element.