Tuning SPP propagation length of hybrid plasmonic waveguide by manipulating evanescent field

Exploring hybrid plasmonic waveguide is a major breakthrough for achieving low-loss lightwave propagation at subwavelength size. Various types of passive hybrid plasmonic waveguides have been reported, but research on active hybrid plasmonic waveguides is very limited. In this study, we propose a tunable hybrid plasmonic waveguide in which its modal characteristics could be dynamically tuned by manipulating the evanescent field of a dielectric waveguide using a closely suspended tuning waveguide. The device can obtain a long-distance lightwave propagation at centimeter scale while maintaining the propagation mode at deep-subwavelength size (2.44λ2/105). Using the proposed tuning method, the propagation length can be tuned more than 100% at the same propagation mode area. The proposed device with a propagation length that can be tuned in a wide range is a promising candidate for building active photonic components. •Modal characteristics of plasmonic waveguide tuned by evanescent field disturbance.•Propagation length could be tuned more than 100%.•Mode area is independent to the propagation length tuning.