sensors Review Roadmap of Terahertz Imaging 2021 Gintaras Valušis 1,2,* , Alvydas Lisauskas 3,4 , Hui Yuan 5 , Wojciech Knap 4 and Hartmut G. Roskos 5 1 Center for Physical Sciences and Technology (FTMC), Department of Optoelectronics, Sauletekio˙ Ave. 3, LT-10257 Vilnius, Lithuania 2 Institute of Photonics and Nanotechnology, Department of Physics, Vilnius University, Sauletekio˙ Ave. 3, LT-10257 Vilnius, Lithuania 3 Institute of Applied Electrodynamics and Telecommunications, Vilnius University, Sauletekio˙ Ave. 3, LT-10257 Vilnius, Lithuania;
[email protected] 4 CENTERA Laboratories, Institute of High Pressure Physics PAS, Sokolowska 29/37, 01-142 Warsaw, Poland;
[email protected] 5 Physikalisches Institut, Goethe-Universität, Max-von-Laue Straße 1, D-60438 Frankfurt am Main, Germany;
[email protected] (H.Y.);
[email protected] (H.G.R.) * Correspondence:
[email protected]; Tel.: +370-5-243-1200 Abstract: In this roadmap article, we have focused on the most recent advances in terahertz (THz) imaging with particular attention paid to the optimization and miniaturization of the THz imaging systems. Such systems entail enhanced functionality, reduced power consumption, and increased convenience, thus being geared toward the implementation of THz imaging systems in real opera- tional conditions. The article will touch upon the advanced solid-state-based THz imaging systems, including room temperature THz sensors and arrays, as well as their on-chip integration with diffrac- tive THz optical components. We will cover the current-state of compact room temperature THz emission sources, both optolectronic and electrically driven; particular emphasis is attributed to the beam-forming role in THz imaging, THz holography and spatial filtering, THz nano-imaging, and computational imaging.