A polarization-insensitive broadband terahertz absorber with a multilayer structure

In this paper, a polarization-insensitive broadband terahertz absorber (PBTA) is presented and demonstrated, which can realize a polarization-insensitive, and broadband perfect absorption in the terahertz regime. By simulation, the polarization-insensitive broadband absorption is over 90%, which runs from 4.904 THz to 6.632 THz (the relative bandwidth is 29.96%), and the obtained absorption remains a good absorption performance with a wide incident angle for both TE and TM waves. The surface current distributions, power loss densities, electric and magnetic field distributions of such an absorber are investigated to figure out the physical mechanism of such a PBTA. The effects structure parameters on the absorption performance are also studied, which will be a guiding to realize a PBTA. The simulated results show that the proposed multilayer structure can help to design a PBTA.