Active terahertz two-wire waveguides.

We demonstrate, by generating a THz electric field directly within the guiding structure, an active two-wire waveguide operating in the terahertz (THz) range of wavelengths. We compare the energy throughput of the active configuration with that of a radiatively coupled semi-large photoconductive antenna, in which the radiation is generated outside the waveguide, reporting a 60 times higher energy throughput for the same illumination power and applied voltage. This novel, active waveguide design allows to have efficient coupling of the THz radiation in a dispersion-less waveguide without the need of involved radiative coupling geometries.