Fig. 1. Structure schematic of (a) metallic hollow waveguide and (b) dielectric-coated metallic hollow waveguide

Fig. 2. Transmission loss of fundamental mode and single-mode transmission range in metallic hollow waveguide

Fig. 3. Transmission loss of fundamental mode and single-mode transmission range in 2-mm-diameter dielectric-coared metallic hollow waveguide

Fig. 4. Single-mode transmission range versus dielectric layer thickness in waveguides with different diameters

Fig. 5. Dispersion coefficients of metallic hollow waveguides with different diameters

Fig. 6. Dispersion coefficients of fundamental mode in 4-mm-diameter dielectric-coated metallic hollow waveguide with different dielectric layer thickness

Fig. 7. Schematic of linearly polarized Gaussian beam coupling to the hollow waveguide

Fig. 8. (a) Coupling coefficient of fundamental mode versus waist/diameter ratio for metallic hollow waveguides with different diameters; (b) coupling coefficient of fundamental mode versus waist/diameter ratio for 4-mm-diameter dielectric-coated metallic hollow waveguides with different dielectric layer thicknesses

Fig. 9. Coupling coefficient of fundamental mode versus wavelength for dielectric-coated metallic hollow waveguides with different dielectric layer thicknesses at optimum waist/diameter ratio

Fig. 10. Electric fields of fundamental mode in dielectric-coated metallic hollow waveguides with different dielectric layer thicknesses of (a) d = 0, (b) d = 100 μm, (c) d = 700 μm, and (d) d = 1600 μm