Perfect adjustable absorber based on Dirac semi-metal high sensitivity four-band high frequency detection

Abstract

In this paper, we propose a highly sensitive, four-band, high-frequency detector with a perfectly tunable absorber based on Dirac semimetals. The design architecture relies on a simple rectangular shape, with absorption rates approaching 100 % at f1 = 9.644 THz, f2 = 9.964 THz, f3 = 11.12 THz, and f4 = 12.432 THz. The symmetric structure exhibits polarization incoherence. Impedance calculations through parameter inversion confirm the occurrence of perfect absorption in the resonance region. By adjusting key parameters of the absorber and modifying the Fermi level of BDS, we demonstrate the absorber's excellent tunability and manufacturing tolerance. Lastly, exploring its sensitivity by altering the external refractive index reveals a maximum refractive index sensitivity of 560 GHz/RIU. Under changing refractive index conditions, the overall absorption rate of the absorber remains above 0.94. In light of these findings, the absorber holds significant reference value in the fields of communication, sensing, and optoelectronic devices.