Coupling and propagation of strong-field THz waves on tungsten wires

Free-space strong-field terahertz (THz) radiation has significant applications in non-equilibrium quantum matter modulation, all-optical electron acceleration and manipulation, THz biomedical effects, and so on. However, certain applications like THz endoscopes, strong-field THz near-field nonlinear optics, and THz high-power devices require a deep understanding of strong-field THz–matter interaction mechanisms. Therefore, improving the manipulation of strong-field THz coupling and propagation characteristics, particularly through the use of metal wire waveguides, is crucial. To this end, we systematically investigate the coupling and propagation characteristics of strong-field THz waves on the surface of tungsten wires and implement two effective coupling methods: two-wire coupling and crossover coupling. This allows for a propagation distance of up to 100 mm along the tungsten surface as THz surface waves. This effective control of strong-field THz waves using metal wires enables the guidance of THz waves from free space into transmission lines and waveguides, which holds significant value for various specific applications.