Terahertz tunable seven-band perfect absorber based on high frequency detection function of Dirac semi-metallic nanowires

This study introduces a tunable perfect absorber in the terahertz range based on Dirac semimetal nanowires, featuring high sensitivity, quality factor, and dual functionality. The absorber achieves perfect absorption across seven bands within the range of 0 - 14.5 THz: f1=5.032 THz (84.43%), f2=5.859 THz (96.23%), f3=7.674 THz (91.36%), f4=9.654 THz (99.02%), f5=11.656 THz (93.84%), f6=12.514 THz (98.47%), and f7=14.01 THz (97.32%). To ensure structural stability during design, the periodicity of the wire array structure was carefully considered. Verification of the absorber's performance was conducted through impedance matching calculations. Analysis of the surface electric and magnetic fields at resonance frequencies elucidates the underlying physical mechanisms governing the absorber's characteristics. Quality factors (Q) for the seven resonance points were computed, with a maximum Q of 219.41 observed. Further investigations by varying the external refractive index reveal maximum sensitivity and figure of merit (FOM) values of 5421.43 (GHz/RIU) and 35.204 (1/RIU), respectively. Then, by discussing the influence of key parameters on the device, we conclude that the device can achieve the choice of dual fixed performance. Dynamic modulation capabilities were demonstrated by varying the Dirac semimetal's Fermi energy (BDS). Additionally, examination of the device's angle of incidence dependence highlighted stable performance in the mid-low frequency range but cautioned about high-frequency range, necessitating careful consideration in practical applications. In conclusion, the proposed absorber holds significant promise for imaging, sensing, and detection applications, offering valuable insights for optoelectronic device design.