This article presents a terahertz imaging system using a waveguide with a reflection topology. The system is based on a femtosecond pulse laser, a transceiver, and a silica pipe hollow-core waveguide. Silicon lens, beam splitter or coupler is no more required to manipulate the terahertz beam in free space, which makes this system setup more compact and easier to align.
Pan, M., Cassar, Q., Fauquet, F., Humbert, G., Mounaix, P., & Guillet, J. P. (2020). Guided terahertz pulse reflectometry with double photoconductive antenna. Applied optics, 59(6), 1641-1647.