Effective single HE11 mode propagation in silver-coated Teflon tubes for THz applications

Developing single-mode waveguides for THz (i.e., 0.3 to 10 THz) applications with low attenuation encounters three major obstacles: in this range (i) dielectric and conductive losses are significant (D. Grischkowsky et al., J. Opt. Soc. Am. B, 7, 2006, 1990), (ii) atmospheric absorption is high (Y. Yang et al., IEEE Trans. THz Sci. Tech., 2, 406–415, 2012), and (iii) the dimensions required are challenging for standard fabrication techniques. Purged dielectric-lined hollow metallic waveguides offer one of the most promising solutions. They have been successfully fabricated with liquid flow polymer deposition for operation above 2 THz (O. Mitrofanov et al., IEEE Trans. THz Sci. Tech., 1, 124–132, 2011) and by assembling dielectric and metallic cylinders for ν < 1 THz (I.A. Tishchenko and A.I. Nosich, IEEE Microw. Magazine, 4, 32–44, 2003).