Fast Three-dimensional Terahertz Imaging with Continuous-wave Photomixing

A high-speed frequency modulated continuous wave (FMCW) radar system is proposed for three-dimensional (3D) terahertz imaging. In order to obtain a high range resolution of mm-order together with fast data acquisition speed, the photonics-based approach is adopted. Thanks to the high-speed frequency sweep of a tunable laser device, the wide bandwidth ranged from 200 GHz to 420 GHz, which corresponds to a range resolution of ~1.3 mm, can be achieved within 35 msec. Furthermore, the 3D imaging of a multi-layer model was demonstrated with quasioptical imaging system, both range and spatial resolution can achieve to ~1.3 mm without using complicated signal processing.