Development of a 600-GHz Optical System for Electromagnetic Field Exposure Assessment Using a Gyrotron

We report the development of an optical system for a 600 GHz gyrotron, which was developed as a light source for electromagnetic field exposure experiments to conduct exposure assessment and investigate the biological effects of the terahertz wave. In this study, we employed triaxial elliptical mirrors to shape the elliptical beam emitted from the gyrotron. The radiation from the optical system was measured and compared with the design value. Furthermore, stable irradiation power control was demonstrated without any change in the gyrotron operating conditions by integrating an irradiation power control module consisting of three wire grids into the beamline.