All-Metal Metamaterial-Based Sensor with Novel Geometry and Enhanced Sensing Capability at Terahertz Frequency

Area of Science:

• Metamaterials
• Plasmonics
• Terahertz (THz) Technology

Background:

• Refractive index sensing is crucial for detecting trace substances.
• Terahertz (THz) spectroscopy offers unique capabilities for material analysis.
• Metamaterial absorbers can enhance sensing performance through tailored electromagnetic responses.

Purpose of the Study:

• To propose and analyze a novel all-metal metamaterial absorber for high-sensitivity refractive index sensing in the THz range.
• To investigate the absorption characteristics and sensing performance of the proposed metamaterial structure.
• To explore potential applications in gas detection and biomolecular analysis.

Main Methods:

• Numerical simulations were performed to design and analyze the metamaterial absorber.
• The structure comprises concentric diamond-shaped gold resonators on a gold plate with varying heights.
• Key performance metrics including absorptivity, sensitivity, and quality factor were evaluated.

Main Results:

• The proposed metamaterial absorber exhibits six ultra-narrow absorption peaks between 5-8 THz.
• Maximum absorptivity reached 99.98% at 6.97 THz with a high quality factor.
• Achieved an average sensitivity of 7.57 THz/RIU, significantly outperforming existing sensors.

Conclusions:

• The novel metamaterial absorber demonstrates exceptional sensitivity for refractive index sensing.
• Its polarization-insensitivity and angular stability make it suitable for diverse THz applications.
• The sensor shows promise for gas detection, biomolecular fingerprinting, and energy harvesting.