A multi-band and polarization-independent perfect absorber based on Dirac semimetals circles and semi-ellipses array*

We design a four-band terahertz metamaterial absorber that relied on the block Dirac semi-metal (BDS). It is composed of a Dirac material layer, a gold reflecting layer, and a photonic crystal slab (PCS) medium layer. This structure achieved perfect absorption of over 97% at 4.06 THz, 6.15 THz, and 8.16 THz. The high absorption can be explained by the localized surface plasmon resonance (LSPR). And this conclusion can be proved by the detailed design of the surface structure. Moreover, the resonant frequency of the device can be dynamically tuned by changing the Fermi energy of the BDS. Due to the advantages such as high absorption, adjustable resonance, and anti-interference of incident angle and polarization mode, the Dirac semi-metal perfect absorber (DSPA) has great potential value in fields such as biochemical sensing, information communication, and nondestructive detection.