A new long-range single nanotube hybrid plasmonic waveguide

Abstract

In this paper, a novel long-range single nanotube hybrid plasmonic waveguide composed of a silicon nanotube and a thin metal layer embedded in it is designed. The geometry of this waveguide is much different from the conventional hybrid plasmonic waveguide such as a tube-wedge or rectangle long-range hybrid plasmonic waveguide. With strong coupling between the silicon nanowire mode and long-range surface plasmon polariton (SPP) mode, both deep subwavelength mode confinement and low propagation loss has been achieved. We evaluate the properties of the ultra-small hybrid plasmonic waveguide including propagation length (L), normalized mode area (Aeff /A0), and figure of merit (FoM). The results show that the designed hybrid plasmonic waveguide enables an ultra-small deep-subwavelength mode in a smaller area than presented long-range hybrid SPP waveguides. What’s more, the propagation length is longer than 1mm and optimization FoM of our waveguide is much larger than 104, which show much better performance that of wedge or rectangle hybrid plasmonic waveguide. Finally, another significant improvement of our structure is that the area of the cross-section is about 0.05um2, which is much smaller than any other presented hybrid plasmonic waveguides.