2D tomographic terahertz imaging using a single pixel detector

Area of Science:

• Physics
• Optics
• Imaging Science

Background:

• Terahertz (THz) imaging offers unique material penetration capabilities.
• Single-pixel imaging (SPI) approaches reduce hardware complexity.
• Accurate modeling of wave propagation is crucial for tomographic reconstruction.

Purpose of the Study:

• To develop and validate a 2D tomographic terahertz imaging setup using SPI.
• To model and compensate for optical effects like refraction, reflection, and diffraction.
• To enable accurate tomographic reconstruction of sample objects.

Main Methods:

• Utilized a liquid helium cooled bolometer as a bucket detector and a mercury-arc lamp as a THz source.
• Employed spatially addressed photodoping of silicon with a near-infrared laser diode modulated by a digital micromirror device for SPI pattern generation.
• Developed a hybrid model combining ray tracing and scalar diffraction theory to simulate wave propagation.

Main Results:

• Achieved good agreement between simulated and measured projections for cylindrical and cuboid polypropylene samples.
• Demonstrated that the developed model effectively accounts for refraction, reflection, and diffraction effects.
• Formulated an optimization problem for tomographic reconstruction based on the validated model.

Conclusions:

• The developed 2D tomographic terahertz imaging system with SPI is effective.
• The hybrid wave propagation model accurately predicts experimental observations.
• The proposed approach facilitates improved tomographic reconstruction in the presence of significant optical distortions.