A Trade-off between Propagation Length and Light Confinement in Cylindrical Metal-Dielectric Waveguides

We theoretically investigate the hybrid plasmonic modes of cylindrical nanocables with gold nanocore and two dielectric nanolayers (SiO₂ and BN). By solving a complete set of Maxwell's equations, the propagation constants and effective radii depending on geometrical parameters are numerically calculated. By declining a trade−off between propagation length and light confinement, high quality hybrid modes which can travel a long range of 120–200λ with a subwavelength effective radius are obtained at the optical wavelength. These modes in one-dimensional cylindrical waveguides should have potential applications in nanoscale optical device designs.