Low-loss THz pulse transmission in commercially available Teflon tubes coated with silver

Silver-coated Teflon hollow waveguides for 0.5-1.5 THz with S/λ² ~10-20 are designed, fabricated and measured using a near-field THz time-domain spectroscopy system. Numerical results predict the fundamental band of the waveguide with 38/120 μm thick Teflon wall to be at ~1.4/0.5 THz. For the waveguide with 120 μm thick inner Teflon wall, the first three bands are observed in transmission spectrum at ~0.5, ~0.9 and ~1.6 THz, and the corresponding field distributions in the waveguide confirm the HE₁₁ mode formation.