Terahertz Broadband Absorber Based on a Combined Circular Disc Structure.

Area of Science:

• Optics and Photonics
• Electromagnetism
• Materials Science

Background:

• Current terahertz absorbers often suffer from complex structures and limited absorption bandwidth.
• Developing efficient and broadband terahertz absorbers is crucial for various applications.

Purpose of the Study:

• To design and simulate a novel broadband terahertz absorber with a simple structure.
• To achieve high absorption rates over an ultra-broadband frequency range.
• To investigate the absorber's performance with different metallic materials and its polarization sensitivity.

Main Methods:

• Utilized the finite element (COMSOL) method for numerical simulation.
• Designed a periodic structure comprising a disk and a concentric ring.
• Analyzed electric field distribution to understand absorption mechanisms.

Main Results:

• Achieved an absorption rate exceeding 99% from 9.06 THz to 9.8 THz.
• Demonstrated an average absorption rate over 97.7% in the ultra-broadband range of 8.62 THz to 10 THz.
• Confirmed perfect absorption with Cu, Ag, and Al, and exhibited strong polarization-insensitivity due to symmetric design.

Conclusions:

• The proposed simple, periodic terahertz absorber exhibits excellent broadband absorption performance.
• The design is material-versatile and polarization-insensitive, facilitating practical implementation.
• This research holds significant potential for terahertz electromagnetic stealth, sensing, and thermal imaging applications.