THz 3D Imaging Based on an Inverse Spherical Synthetic Aperture

This paper presents to our knowledge the first high-resolution 3D reconstruction in the terahertz frequency range using an inverse spherical synthetic aperture. A wide-bandwidth terahertz time-domain spectroscopy system with antennas operating in divergent reflection geometry is used together with a low-cost 3D-printed device to rotate an object in azimuth and elevation. The method is evaluated by performing a 3D reconstruction of a 20-sided metal dice. The obtained resolution is 50 $\mu$m in all directions.