Real-time two-dimensional terahertz tomography

Real-time two-dimensional (2D) terahertz (THz) tomography is proposed for 2D cross-sectional imaging of moving objects. The proposed method is based on combined use of noncollinear two-dimensional free-space electro-optics sampling (2D-FSEOS) and line focusing of terahertz beam. There are no needs of mechanical scanning elements for time delay and sample position, which are essential for conventional THz tomography. We apply real-time 2D THz tomography to monitoring of the paint thickness in a moving paint sample. The proposed method provides a powerful tool for noninvasive and noncontact probing in the fields of nondestructive testing and biomedical diagnostics.