Hybrid cylinder-triangle plasmonic waveguide for low loss propagation and subwavelength confinement

In this paper, we design and analyze a novel hybrid cylinder-triangle plasmonic waveguide (HCTSPPs), which is composed of three high index dielectric cylinders placed above an equilateral triangular metal with the center corresponding to the three vertices of the triangle. The strong hybridization coupling between Si dielectric cylinders (SDCs) and the metallic triangular wedge SPP (WSPPs) enables enhanced field confinement inside the gap region as well as long propagation length. It is also shown that relative long propagation length (100 lambda) and ultra-small deep subwavelength effective mode area (lambda(2) /4000) can be realized by gradual modification of the geometric size, which is one-order improvement compared to other hybrid waveguides. Moreover, an investigation of the effects of actual fabrication errors on the mode properties about HCTSPPs indicates that mode properties are also quite tolerant to fabrication deviations. The proposed waveguide could be applied to subwavelength laser devices and optically integrated circuits.