Square-package arrays for efficient trapping of terahertz waves.

Area of Science:

• Optics and Photonics
• Materials Science
• Electromagnetism

Background:

• Metamaterial absorbers are crucial for manipulating electromagnetic waves.
• Broadband absorption in the terahertz (THz) spectrum remains a significant challenge.
• Existing THz absorbers often suffer from narrow bandwidth and sensitivity to incident parameters.

Purpose of the Study:

• To design and demonstrate a broadband metamaterial absorber operating in the THz range.
• To investigate the absorption mechanism and performance characteristics of the proposed structure.
• To evaluate the device's suitability for practical applications like THz shielding and sensing.

Main Methods:

• A metamaterial absorber composed of a doped silicon substrate and a SU-8 coated doped silicon square array was fabricated.
• Numerical simulations were employed to analyze absorption spectra and electric field distributions.
• The impedance matching principle was used to verify near-perfect absorption.
• The effects of incident angle, polarization, and structural variations were systematically studied.

Main Results:

• The proposed absorber achieved an average absorption of 94.42% from 0.5-8 THz.
• Absorption exceeded 90% over a wide frequency range of 1.44-8 THz.
• The structure exhibited polarization insensitivity and wide-angle absorption capabilities.
• Good process tolerance was demonstrated, indicating robustness.

Conclusions:

• The developed metamaterial absorber offers significant broadband performance in the THz spectrum.
• Its polarization-insensitive and wide-angle characteristics make it highly versatile.
• The device shows great potential for applications in THz shielding, cloaking, sensing, and energy harvesting.