Terahertz Constant Velocity Flying Spot for 3D Tomographic Imaging

Area of Science:

• Physics
• Chemistry
• Imaging Science

Background:

• Terahertz (THz) tomography offers non-ionizing imaging capabilities.
• Characterizing heterogeneous semitransparent media requires advanced 3D imaging techniques.
• Existing methods may struggle with complex sample geometries.

Purpose of the Study:

• To develop and validate a terahertz tomography technique for 3D chemical absorption imaging.
• To assess the technique's applicability to non-axisymmetric and complex samples.
• To demonstrate the potential for phase separation analysis in heterogeneous media.

Main Methods:

• Utilized constant velocity flying spot scanning for terahertz radiation illumination.
• Employed a hyperspectral thermoconverter and infrared camera as the detection system.
• Reconstructed the 3D absorption coefficient using a back-projection method based on the inverse Radon transform from sinogram data.

Main Results:

• Successfully reconstructed the 3D absorption coefficient of a hydroalcoholic gel sample.
• Demonstrated the technique's capability to image samples with complex, non-axisymmetric shapes.
• Achieved 3D qualitative chemical information, including potential phase separation, within the terahertz spectral range.

Conclusions:

• The developed terahertz tomography technique is effective for 3D chemical imaging of complex samples.
• The method provides valuable insights into the composition of heterogeneous semitransparent media.
• This technique shows promise for analyzing materials with intricate structures and varying compositions.