Metasurface Terahertz Perfect Absorber with Strong Multi-Frequency Selectivity.

Area of Science:

• Metamaterials and Nanophotonics
• Terahertz (THz) Technology
• Electromagnetic Wave Absorption

Background:

• Metasurface perfect absorbers are crucial for various THz applications.
• Achieving multi-frequency selectivity and wide incident angle compatibility remains a challenge.

Purpose of the Study:

• To design and analyze a novel metasurface terahertz perfect absorber.
• To achieve multi-frequency selectivity and good incident angle compatibility.
• To demonstrate tunable absorption modulation.

Main Methods:

• Utilized a double-squared open ring structure for the metasurface design.
• Performed electromagnetic simulations to analyze absorption peaks and Q-factors.
• Investigated the effects of polarization modes, incident angles, and structural parameters.
• Incorporated tunable materials like 2D materials and photosensitive semiconductors.

Main Results:

• Five selective absorption peaks were observed between 0-1.2 THz, with absorptions exceeding 86%.
• High frequency selectivity was achieved at 0.836 THz (Q-factor=167.20) and 0.996 THz (Q-factor=166.00).
• The absorber showed minimal absorption change for TM mode across incident angles from 0-80°.
• Tunable modulation with a modulation depth of ≈100% was achieved using photosensitive silicon.

Conclusions:

• The designed metasurface absorber offers excellent multi-frequency selectivity, wide incident angle compatibility, and tunable absorption.
• The findings contribute to advancements in terahertz wave absorption and spectral control.
• Potential applications include resonators, bio-detection, sensors, and imaging systems.