All-Dielectric Metasurface-Based Terahertz Molecular Fingerprint Sensor for Trace Cinnamoylglycine Detection

Area of Science:

• Biomedical Engineering
• Spectroscopy
• Materials Science

Background:

• Terahertz (THz) spectroscopy is a label-free sensing technology for biomolecule detection.
• Current THz methods face limitations in sensitivity and discrimination, hindering wider adoption.
• Enhanced molecular fingerprint detection is crucial for sensitive biomolecule identification.

Purpose of the Study:

• To propose and investigate a novel metasurface for enhanced molecular fingerprint detection using THz spectroscopy.
• To improve the sensitivity and discrimination capabilities of THz sensing for biomolecules.
• To demonstrate the application of this technology for detecting trace amounts of analytes and disease biomarkers.

Main Methods:

• Designed a metasurface comprising lithium tantalate triangular prism tetramers in a square quartz lattice.
• Utilized the finite-difference time-domain (FDTD) method to explain the physical mechanism.
• Evaluated THz sensing performance by measuring the quality factor (Q-factor) and figure of merit (FoM).

Main Results:

• The designed metasurface achieved a high Q-factor of 231 and an FoM of 609.
• Varying the incident angle of THz waves significantly enhanced the molecular fingerprint signal.
• Achieved a sensitivity limit of 1.23 μg·cm-2 for detecting cinnamoylglycine.

Conclusions:

• The proposed metasurface significantly enhances molecular fingerprint signals in THz spectroscopy.
• This technology enables highly sensitive detection of trace analytes, with potential for early disease diagnosis.
• Offers critical insights for advanced THz wave applications in biomedicine, including urinary biomarker detection for diseases like GDM.