MXene-based hybrid plasmonic waveguide by inserting low refractive index layer for long-range propagation

Abstract

The unique plasmonic properties of MXene in the near-infrared region have attracted increasing attention, but the surface plasmons of MXene still face problems of poor confinement and large propagation loss. In this work, an MXene hybrid planar waveguide at the communication wavelength was proposed by inserting a low refractive index layer beneath the MXene materials. The introduction of this low refractive index dielectric layer (SiO₂) can dramatically expand the propagation distance and improve the localization of the electric field. When the thickness of SiO₂ is only 20 nm, the propagation distance can be increased to over $10\mu m$, which is 100 times that of MXene waveguides without SiO₂ layers. MXene hybrid plasmonic waveguides are competitive compared to other typical plasmonic waveguides, such as Au, Ag, and graphene at the wavelength of $1.55\mu m$. The silicon-on-insulator (SOI)-based MXene hybrid plasmonic waveguide was further designed. By optimizing the structure, the figure of merit has risen by an order of magnitude in contrast to MXene waveguide structures. These findings will contribute to the practical application and development of MXene surface plasmonic components.