A hybrid wedge-to-wedge plasmonic waveguide with low loss propagation and ultra-deep-nanoscale mode confinement

The well-known tradeoff between the propagation loss and mode confinement is a critical consideration for the plasmonic waveguide structures. Aiming to overcome this limitation, in this paper, we propose a compact plasmonic waveguide consisting of two identical dielectric wedge waveguides symmetrically placed on each side of a nanowedge-patterned thin metal film. The systematical analysis has demonstrated that the light can be confined to approximate 3000th of the diffraction spot size (ranging from λ²/10 604 to λ²/972) without sacrificing the propagation length (ranging from 1680 to 4724 μm). Compared to the recent published structure which achieved the best tradeoff, to the best of our knowledge, the proposed waveguide could achieve a 9-fold enhanced mode confinement for the same propagation length and a 2.4-fold outspread propagation length for the same mode confinement.