Design of a Polarization-Insensitive and Broadband Tunable Terahertz Absorber Based on VO₂ Phase-Change Metamaterials

The paper proposes a polarization-insensitive and broadband tunable terahertz absorber based on VO₂ phase-change metamaterials to tackle critical technical issues in conventional terahertz absorbers, including poor frequency tunability, large structural size, and limited bandwidth coverage. Featuring a three-layer configuration composed of a bottom Au reflective layer, a middle SiO₂ dielectric layer, and a top patterned VO₂ functional layer, the absorber achieves an ultrabroadband absorption bandwidth of 6.7 THz from 7.3 to 14 THz, with an absorption efficiency stably exceeding 90% across the entire band, indicating near-perfect absorption. Leveraging the distinctive phase-transition characteristics of VO₂, the absorber enables flexible tuning of absorption properties while remaining insensitive to both TE and TM polarization modes. This design integrates broad bandwidth, high performance, and tunability, offering a novel strategy for terahertz absorber design. It holds significant potential for applications in high-speed communication, high-resolution imaging, and high-precision sensing, thereby driving technological advancements in these cutting-edge fields.