Hollow hybrid plasmonic waveguide for nanoscale optical confinement with long-range propagation

A novel (to our knowledge) hybrid plasmonic (HP) hollow waveguide is proposed for nanoscale optical confinement. The light is guided, with improved propagation characteristics, in an air slice sandwiched between metal and silicon. The optical mode in silicon is dragged toward the metal-dielectric (air) interface to make it a HP mode by optimizing the waveguide dimensions. In comparison to the hybrid mode confined in the dielectrics, the air-confined hybrid mode exhibits a smaller effective mode area A(m)=0.0685/μm² and longer propagation distance L(p)=142  μm with a low modal propagation loss of 0.03  dB/μm at optimized values of the width and height of the air slice.