Simplifying THz-CT-CW Imaging System Using Vector Network Analyzer and Two Ellipsoid Mirrors

The traditional THz-CT-CW (CT: computed tomography; CW: continuous wave) imaging system separately employs a transmitter and a receiver that extra requires a chopper due to the principle of the receiver. And that system uses at least 4 lenses/mirrors to first collimate the emitted wave and then focus it on the sample. In this paper, we applied a vector network analyzer (VNA) to the THz-CT-CW system to replace the transceiver devices and omit the optical chopper for improving the transceiver device integration. And learning from the free-space method system, we adopt 2 ellipsoid mirrors to the THz-CT-CW system to directly focus the emitted wave on the sample for reducing the number of lenses/mirrors used in the traditional system. Finally, we verified the feasibility of the proposed system according to the imaging results from the experiment. The results show that VNA can be replaceable in THz-CT-CW and using the 2 ellipsoid mirrors is feasible.