Cylindrical aperture three-dimensional synthetic aperture imaging with pulsed terahertz waves

Area of Science:

• Physics
• Engineering
• Optics

Background:

• Traditional synthetic aperture imaging often relies on frequency scanning, which is challenging at higher frequencies.
• Terahertz (THz) imaging offers unique capabilities for non-destructive evaluation due to its spectral properties.

Purpose of the Study:

• To develop and demonstrate a 3D synthetic aperture imaging method using pulsed terahertz waves.
• To achieve high-resolution, rapid, and non-destructive imaging of objects with complex structures.

Main Methods:

• Utilized a terahertz time-domain spectrometer with photoconductive antennas for broadband pulse generation and detection.
• Employed a novel imaging algorithm, theoretically analyzed and numerically validated using the finite-difference time-domain method.
• Demonstrated the system's capability using a detailed key and an optically opaque plastic pen.

Main Results:

• Achieved a resolution of 0.3 mm (linear) and 0.1 mm (circular).
• Successfully reconstructed 3D images of a pen's internal cartridge, showcasing non-destructive evaluation.
• Significantly improved imaging speed compared to step-by-step scanning methods.

Conclusions:

• The pulsed terahertz synthetic aperture imaging method is effective for high-resolution 3D imaging.
• This technique offers advantages over conventional methods, including faster imaging and avoidance of image degradation.
• The method shows significant potential for non-destructive evaluation of objects with complex surfaces and internal structures.