Bandwidth-tunable THz absorber based on diagonally distributed double-sized VO₂ disks

Area of Science:

• Materials Science
• Optics
• Nanotechnology

Background:

• Terahertz (THz) absorbers are crucial for stealth technology.
• Phase-changing vanadium dioxide (VO2) offers tunable absorptance.
• Existing THz absorbers often lack sufficient absorption bandwidth.

Purpose of the Study:

• To design and investigate a novel three-layer THz absorber with enhanced bandwidth.
• To explore the tunability of absorptance and bandwidth using VO2 disks.
• To evaluate the polarization and angular dependence of the absorber's performance.

Main Methods:

• Finite element simulation (FES) was employed to model the THz absorber.
• The absorber structure consists of diagonally distributed double-sized VO2 disks on a silica-coated gold film.
• Key parameters such as disk size and VO2 conductivity were varied.

Main Results:

• The proposed structure achieves a superposition of three resonant absorption peaks, broadening the absorption band.
• Absorption bandwidth is adjustable from 2.63 to 5.04 THz by altering VO2 disk sizes.
• Peak absorptance is continuously tunable from 9.8% to 96% by adjusting VO2 conductivity.
• The absorber demonstrates polarization-insensitivity and wide-angle absorption capabilities.

Conclusions:

• The developed THz absorber offers a wide and adjustable absorption bandwidth.
• Tunable absorptance and robust performance make it suitable for intelligent stealth materials.
• This research advances the development of adaptive THz stealth technologies.