Research on broadband terahertz absorber based on Dirac semi-metal and water mixture

Abstract:

In this paper, a terahertz (THz) dual tunable broadband metamaterial absorber based on bulk Dirac semi-metal (BDS) and water is proposed. Unlike the traditional single-control vibration absorber, the vibration absorber can be adjusted by temperature and Fermi level. The simulation results show that when the water temperature and Fermi level of BDS are adjusted at 15 ℃ and 30 meV, respectively, the absorption rate is greater than 90% in the frequency range of 2.97~6.11 THz. Compared with the absorber without water injection or BDS mode, the bandwidth with an absorption rate of more than 90% has been significantly improved. In addition, by adjusting the temperature of water or Fermi energy of BDS, the absorption bandwidth and intensity of the absorber can be controlled independently or jointly, without redesigning the device. We use the characteristic that the dielectric constant of water can be adjusted by temperature, as well as the characteristic that BDS can be controlled by Fermi energy, the action mechanism of the dual-control absorber is explained. In this paper, the physical mechanism of broadband absorption is studied and clarified by means of field analysis. Based on its excellent performance, our research results may have potential applications in the field of thermal detectors and terahertz imaging.