Angularly stable terahertz multiband LiNbO₃-polymer hybrid metamaterial for microfluidic refractive index sensing

Area of Science:

• Metamaterials
• Terahertz Spectroscopy
• Sensing Technology

Background:

• Terahertz (THz) technology offers unique capabilities for non-ionizing spectroscopy.
• Metamaterials provide a platform for manipulating electromagnetic waves at THz frequencies.
• Developing sensitive THz sensors is crucial for various scientific and medical applications.

Purpose of the Study:

• To demonstrate a lithium niobate-polymer hybrid metamaterial (LPHM) for THz applications.
• To investigate the bulk refractive index (RI) sensing performance of the LPHM.
• To optimize LPHM parameters for enhanced sensing capabilities.

Main Methods:

• Finite-element method (FEM) simulations were employed for parameter optimization.
• The study analyzed the reflection and absorption spectra of the LPHM in the 1-10 THz band.
• Refractive index sensitivity and detection limit were evaluated.

Main Results:

• The LPHM exhibited four distinct spectral peaks in the 1-10 THz range.
• Spectral peak positions were sensitive to changes in LPHM structural parameters (period, side length, layer widths).
• The LPHM achieved a high RI sensitivity of 11.5 µm/RIU with a detection limit of 2.9×10⁻⁴ RIU.

Conclusions:

• The demonstrated LPHM shows excellent refractive index sensing performance.
• The material possesses wide angular and good structural stability.
• Potential applications include pharmacological biodevices, THz immunosensing, and biochemical substance detection.