Terahertz fan-beam computed tomography

Area of Science:

• Physics
• Engineering
• Imaging Technology

Background:

• Conventional terahertz computed tomography (CT) systems often use parallel beams and a symmetric 4-f structure.
• These systems can be limited by data acquisition time and imaging depth.
• Advancements in terahertz beam technology are needed for more efficient 3D imaging.

Purpose of the Study:

• To propose and demonstrate a novel terahertz (THz) fan-beam computed tomography (CT) system.
• To utilize a continuous-wave sheet beam for improved imaging performance.
• To establish a foundation for second-generation THz CT systems.

Main Methods:

• Development of a terahertz (THz) fan-beam computed tomography (CT) system.
• Employment of a 0.3 THz continuous-wave sheet beam, which expands in a fan shape.
• Reconstruction of a 3D metal rod structure within a carton for feasibility demonstration.

Main Results:

• The proposed fan-beam THz CT system successfully reconstructed the 3D internal structure of the metal rod.
• The system utilizes a diffraction-free sheet beam, enabling propagation-invariant focal lines and extended depth-of-field.
• Data acquisition time is reduced due to the use of a linear array detector.

Conclusions:

• The developed fan-beam THz CT system represents a significant advancement, serving as a template for second-generation THz CT.
• This technology offers an effective additional method for nondestructive testing.
• The system retains geometrically magnified features of cross-sectional structures during 3D imaging.