Dual-band tunable terahertz absorber based on all-dielectric InSb metamaterials

We propose a dual-band tunable terahertz (THz) absorber based on all-dielectric InSb metamaterials. This absorber consists of a resonant structure at the top and a dielectric substrate at the bottom. The resonant structure layer interacts with THz waves to achieve high-efficiency absorption, while the dielectric substrate layer not only provides support but also effectively prevents THz waves from penetrating the absorber. Simulation results show that under room temperature conditions (T=300K), the absorber achieves absorption rates of 96.85% and 98.76% at the frequencies of 0.366THz and 0.991THz, respectively. As the temperature increases, these two absorption peaks shift towards a higher frequency range. Based on the unique properties of InSb, the frequency shift range of the proposed absorber can be tuned through external thermal excitation, with a maximum of 0.24THz. Meanwhile, the absorber maintains a high absorption rate of over 85%. The incorporation of InSb metamaterials enables temperature tunability, allowing the absorber to exhibit enhanced performance over a broader temperature range, making it suitable for sensor devices that require precise control over both absorption efficiency and temperature tuning.