High Resolution VNA THz Imaging for Large Distances

In this paper, we employ a terahertz vector network (VNA) analyzer system for high resolution imaging using a Kirchhoff migration algorithm. The imaging method makes use of a divergent terahertz beam and eliminates the requirement for any optomechanical elements. This enables high resolution imaging at distances larger than 1 m. Moreover, a method is presented which compensates for the low relative bandwidth of the VNA compared with typical terahertz time-domain spectroscopy systems. We validate the performance of the method with 2-dimensional 360° imaging of a sample at a distance of 1.35 m.