FDTD-based quantitative analysis of terahertz wave detection for multilayered structures.

Area of Science:

• Physics
• Materials Science
• Engineering

Background:

• Terahertz pulsed imaging (TPI) quantitatively characterizes multilayered media.
• Existing terahertz wave propagation models are often 1D or 2D and simplify dielectric layer dispersion.
• Advanced modeling is crucial for expanding terahertz technology in nondestructive testing.

Purpose of the Study:

• Establish a theoretical framework for quantitative characterization of multilayered media using terahertz waves.
• Develop and validate a 3D model for terahertz wave interaction with multilayered structures.
• Investigate the potential for defect detection in layered materials.

Main Methods:

• Developed a 3D model based on the finite difference time domain (FDTD) method.
• Simulated terahertz wave reflection from pharmaceutical tablets with varying coating thicknesses and refractive indices.
• Modeled a three-layered medium to simulate material defects.

Main Results:

• The 3D FDTD model accurately predicted terahertz wave reflection from coated pharmaceutical tablets.
• Simulated results showed good agreement with experimental data from a commercial TPI system.
• The model demonstrated potential for identifying defects in multilayered samples.

Conclusions:

• The proposed 3D FDTD model provides a robust theoretical framework for terahertz-based characterization of multilayered media.
• This advanced modeling approach enhances the quantitative capabilities of TPI for materials analysis and defect detection.
• The study validates the use of terahertz technology for nondestructive testing of complex layered structures.