Computed tomography using broadband Bessel THz beams and phase contrast.

Area of Science:

• Physics
• Imaging Science
• Optics

Background:

• Conventional Gaussian beams in terahertz computed tomography (CT) have limited depth-of-field, affecting 3D reconstruction quality.
• Nondiffractive beams offer propagation invariance and extended focal depth, potentially overcoming limitations of Gaussian beams.

Purpose of the Study:

• To demonstrate the capability of terahertz computed tomography (CT) using broadband Bessel beams.
• To evaluate the improvement in 3D image reconstruction using Bessel beams compared to conventional methods.
• To investigate the impact of phase-contrast mechanisms on spatial resolution and image quality.

Main Methods:

• Utilized broadband Bessel terahertz (THz) beams for computed tomography (CT) imaging.
• Employed a backprojection algorithm for 3D image reconstruction.
• Incorporated a phase-contrast mechanism to enhance image resolution.

Main Results:

• Achieved a considerable improvement in the 3D reconstruction of a synthetic sample using THz Bessel beams.
• Demonstrated full reconstruction of object structure exclusively with THz Bessel beams.
• Observed enhanced spatial resolution and improved reconstructed images due to the phase-contrast mechanism.

Conclusions:

• Nondiffractive Bessel beams show significant potential for improving 3D image reconstruction in terahertz computed tomography (CT).
• The extended depth-of-field and propagation invariance of Bessel beams are key to enhanced reconstruction.
• Phase-contrast further refines image quality, highlighting the utility of Bessel THz CT for detailed structural analysis.