A Compound THz Meta-surface Absorber with Polarization Insensitivity and Angular Stability

In this paper, a wideband terahertz meta-surface absorber with ultra-thin thickness is proposed. The meta-surface unit cell is composed of four-square unit cells in two different sizes. The the absorption higher than 90% from 3.24 to 3.98THz is achieved which can be regarded as a perfect terahertz absorber. Due to the symmetrical layout of meta-surface unit cell, the absorption spectrum can be maintained for any linear polarized terahertz wave, and the absorptance can be kept higher than 80% while the incident angle increases before 45 degrees. Furthermore, the thermal response is calculated to be 0.23 K center dot mm(2)/ mu W that well suited the requirements of FPA detectors.