Hybrid plasmonic waveguide made of a nanofiber attached to a metal film

We report a hybrid plasmonic waveguide consisting of a nanofiber coupled with a copper film on a silicon substrate. The nanofiber can be flexibly placed on the copper film to generate a highly localized optical field. Due to the easy attachment of the nanofiber to the metal surface, it is convenient to reconfigure the hybrid plasmonic waveguide. We investigate two waveguide systems with either a straight or a curved nanofiber coupled with the copper film. The straight nanofiber could excite two hybrid plasmonic modes, leading to periodic field oscillation along the metal surface. In contrast, the curved nanofiber can only excite the fundamental mode, owing to the adiabatic mode conversion before the hybrid waveguide. The propagation loss of the fundamental hybrid plasmonic mode is measured to be around 25.32 dB/mm for a nanofiber radius of 0.8 mu m. (C)2015 Optical Society of America