Propagation Properties of Symmetric Surface Plasmon Polaritons Mode in ${\rm Au}/{\rm Al}_{2}{\rm O}_{3}/{\rm Au}$ Waveguide

Propagation properties of symmetric surface plasmon polariton (SPP) mode excited through a dipole embedded in Al₂O₃ layer in Au/Al₂O₃/Au waveguide have been investigated. The skin effect of symmetric SPP mode vertical to Al₂O₃/Au interface is presented. The skin depths in the Au layer and in the intermediate Al₂O₃ layer are 12 and 24 nm, respectively. Moreover, the propagation properties of symmetric SPP mode along Al₂O₃/Au interface are also analyzed. The propagation lengths of electric and magnetic field component are 0.4 and 0.8 μm, respectively. It is expected that this study will provide additional understanding to the coupling between SPP sources and plasmonic waveguides.