Bifocal dual reflector system for active terahertz imaging

Abstract

This paper introduces a method for optimizing the terahertz (THz) imaging resolution in a specified field of view (FoV) for a scanning dual reflector system (Gregory or Cassegrain system) based on the theory of field curvature. The authors built a Gregory scanning system to verify the ability of this method. The operating frequency of the verification system is 220 GHz, the FoV at a specified distance of 8 m is approximately 50 cm * 100 cm, and the imaging resolution throughout the entire FoV is better than 3 cm. Experimental results show that the imaging resolution of the classical dual reflector system can be optimized, and the proposed verification system can realize active THz imaging of the human body.