Design and performance study of a multiband metamaterial tunable thermal switching absorption device based on AlCuFe and VO2

In this paper, we propose a multiband adjustable metamaterial absorption device based on a Dirac semimetal (BDS) AlCuFe and a thermally controlled phase-change material VO₂. The absorption device has an axially symmetric structure, resulting in polarization-independent characteristics, and when VO₂ is in a high-temperature metal state, ultra-high absorption rates and sensitives at frequencies of M₁ = 2.89 THz, M₂ = 7.53 THz, M₃ = 7.97 THz, and M₄ = 9.02 THz are achieved. Using a parameter inversion method, we calculated the impedance of the absorber, proving that it achieves impedance matching and produces perfect absorption in the resonance region. Additionally, we changed the physical and chemical parameters of the absorption device, demonstrating the device's excellent tunability and manufacturing tolerance. Furthermore, by lowering the temperature of VO₂ to that of a low dielectric state, additional resonant peaks with ultra-high absorption rates at frequencies M₅ = 5.62 THz, M₆ = 7.16 THz, M₇ = 7.64 THz, and M₈ = 8.80 THz were obtained, broadening the absorption band of the device. Lastly, we investigated the detection sensitivity of the device by changing the external refractive index, resulting in a maximum sensitivity of 2229 GHz RIU⁻¹. To sum up, the absorption device has great application potential in the fields of communication, sensing, temperature detection and photoelectric instruments.