3D-printed dielectric helical THz waveguides

We report on a 3D-printed helical waveguide to increase the bandwidth of a low-loss dielectric tube Terahertz (THz) waveguide. The helical design prevents the multiple reflections in the tube cladding hence avoiding the pronounced interference pattern in the attenuation spectrum of a dielectric tube waveguide. Both THz time-domain spectroscopy (THz-TDS) measurements and finite-difference time-domain (FDTD) simulations consistently confirm the extended bandwidth of the dielectric helical waveguide. In addition, numerical investigations reveal that the broadband behavior of the 3D-printed helical waveguide is not critical with respect to the absorption of the waveguide material.