Hybrid plasmon waveguide leveraging Bloch surface polaritons for sub-wavelength confinement

A novel hybrid plasmonic waveguide based on a guided Bloch surface polariton structure is proposed and investigated. This hybrid waveguide overcomes the weak confinement in the Bloch surface polariton structure caused by the diffraction limitation. By introducing a metal stripe near the dielectric ridge located on the periodic multilayer structure that is designed to support a TM polarized Bloch surface polariton, a sub-wavelength scale electric field confinement is realized. The coupling of the Bloch surface polariton and the surface plasmon polariton results in a strong field distribution within the gap between the metal stripe and the dielectric ridge. The variation of the characteristic of the hybrid mode is revealed via tuning the height of the ridge and the coupling distance. Sub-wavelength scale mode size is realized as well as a propagation length of about 100 μm.