Research on an imaging system based on cold cathode terahertz gyrotron

Terahertz waves, with the advantages of strong penetrability and low damaging, can be applied to develop non-destructive testing (NDT), security detection and medical imaging. As a vacuum electronic radiation source of high-power, long-pulse terahertz waves, gyrotron therefore has great potential in transmission imaging and NDT. A terahertz imaging system based on a cold cathode gyrotron is designed in this paper. In the system, the wave of higher-order mode generated by the gyrotron is converted to a quasi-optical Gaussian beam by a mode converter, which then passes through the object and is received by a terahertz detector for analyzing and imaging. Metal and dielectric objects are scanned in the experimental study and clear transmission images are obtained.