THz Polarimetric Imaging of Carbon Fiber-Reinforced Composites Using the Portable Handled Spectral Reflection (PHASR)...

Area of Science:

• Materials Science
• Spectroscopy
• Nondestructive Testing

Background:

• Terahertz (THz) spectroscopic imaging is advancing nondestructive testing (NDT).
• Polarization information in THz waves is crucial for material characterization.
• Limited availability of polarimetric imaging devices hinders polarization-resolved THz imaging in NDT.

Purpose of the Study:

• To demonstrate polarization-resolved THz imaging using a portable scanner for industrial carbon fiber composites.
• To investigate the utility of THz polarimetry for characterizing anisotropic materials.

Main Methods:

• Utilized a portable, handheld THz imaging scanner equipped with two orthogonal photoconductive antennas.
• Simultaneously captured THz wave polarizations in two channels.
• Analyzed THz Stokes vectors derived from the captured polarimetric data.

Main Results:

• Observed significant polarimetric differences between orthogonal THz channels for carbon fiber composites.
• Attributed these differences to the anisotropic conductivity of the material.
• Successfully visualized superficial and underlying interfaces of the composite laminate using both polarimetric channels.

Conclusions:

• THz polarimetry, enabled by portable imaging devices, offers valuable insights into anisotropic materials like carbon fiber composites.
• This technique can be applied to assess coatings and surface quality on carbon fiber-reinforced substrates.
• The study highlights the potential of THz polarimetric imaging as a powerful NDT modality.