High sensitivity five band tunable metamaterial absorption device based on block like Dirac semimetals

This paper proposes a metamaterial absorption device (MAD) based on Block Dirac semimetal (BDS), which exhibits five band perfect absorption in 5.96 THz, 7.86 THz, 9.84 THz, 11.91 THz, 12.22 THz, the absorption rates of M1-M5 are 0.987, 0.998, 0.997, 0.996, 0.999 and Q-factors are 54.36, 131.06, 61.61, 99.75, 102.58, respectively. The MAD has a three-layer structure consisting of substrate gold, silica, and top layer BDS, where BDS is designed as a cylindrical and circular microstructure. And polarization insensitivity due to the symmetry of the design. According to calculations, the MAD conforms to the impedance matching theory. In the analysis of the electric field diagram, it was revealed that the absorption of electromagnetic waves comes from LSPR and guided mode resonance effects. Based on the characteristics of BDS, this device can be tuned with changes in BDS Fermi energy, while also possessing certain physical tuning capabilities. When exploring the refractive index sensitivity of the device, we found that it has a high refractive index sensitivity. Among them, the sensitivity of M1-M5 is 2000 GHz/RIU, 570 GHz/RIU, 3970 GHz/RIU, 3000 GHz/RIU, and 1000 GHz/RIU, respectively Overall, this device has strong application prospects in sensing fields such as biomedicine.