ObjectiveSurface plasmon Polariton (SPP) can bind the light field in a region far smaller than its free space wavelength, which is a technique that can break the diffraction limit and help to reduce the size of optical devices. Since SPP has obvious advantages at deep subwavelength scales, it is regarded as the key to manipulating optical signals at subwavelength scales. Terahertz (THz) waveguides are the basic components for the construction of various terahertz functional devices, which is of great significance for the realization of on-chip terahertz functional devices and ultra-wideband terahertz communication in the future. The surface conductivity of graphene is almost pure imaginary at the terahertz band, and it can exhibit properties similar to metal materials, so it can be regarded as a very thin metal layer, and the graphene plasmons also has low loss, strong confinement and tunability. However, in the terahertz band, although SPP has a long propagation length and low transmission loss, due to the difficult to adjust the properties of metal materials, its binding on the metal surface is still weak, so it is still difficult to achieve the effect of compact photon integration. A hole-based graphene hybrid plasmonic waveguide is proposed. By adjusting the parameters and the chemical potential of graphene, the mode characteristics and transmission characteristics of the hybrid mode are studied numerically. Compared with the hybrid waveguide without air hole, the hybrid waveguide has strong binding and low loss, which is more conducive to photon integration and achieves better transmission performance. In addition, the crosstalk characteristics between the two hybrid plasma waveguides are also studied to further achieve ultra-low crosstalk. The low crosstalk characteristics of this structure will have broad development prospects in future terahertz integrated circuits.MethodsThe characteristic patterns of the hole-based graphene hybrid plasmonic waveguide system with different structural parameters and chemical potential of graphene are calculated by finite element analysis method. In the process of analysis, it is assumed that the calculation region in x-direction and y-direction is infinite to ensure accurate eigenvalues. The mode effective index and propagation length are determined by the real and imaginary parts of the eigenvalue, respectively.Results and DiscussionsThe proposed hole-based graphene hybrid plasmonic waveguide optimizes the transmission characteristics of the hybrid waveguide by changing the gap height, the size of air hole and the chemical potential of graphene. Firstly, we discuss the effect of the side length of air hole on the mode characteristics of basic hybrid plasma guided by hole-based graphene hybrid plasmonic waveguide. When the side length of air hole increases from 15 μm to 19 μm, the normalized mode area A_eff/A₀ is as small as 2.77×10⁻⁴, the corresponding propagation length is 21.8 μm, and the figure of merit is 38.7. Secondly, we discuss the effect of gap height on the mode properties of the basic hybrid plasma. The gap height is reduced from 2.5 μm to 0.5 μm, the normalized mode area A_eff/A₀ is as small as 2.77×10⁻⁴, the corresponding propagation length is 21.8 μm, and the figure of merit is 38.7. Thirdly, we discuss the effect of the chemical potential of graphene on the mode properties of the basic hybrid plasma. The variation range of the chemical potential of graphene is changed between 0.4 eV and 1 eV, and the side length of air hole is increased from 15 μm to 19 μm, the normalized mode area A_eff/A₀ is as small as 2.77×10⁻⁴, the corresponding propagation length is 21.8 μm, and the figure of merit is 38.7. When the change range of the chemical potential of graphene is controlled between 0.4 eV and 1 eV, and the gap height is reduced from 2.5 μm to 0.5 μm, the normalized mode area A_eff/A₀ is as small as 2.77×10⁻⁴, the corresponding propagation length is 21.8 μm, and the figure of merit is 38.7. Finally, the crosstalk between two hole-based graphene hybrid plasmonic waveguides could be reduced to 22 μm by changing the structural parameters and the chemical potential of graphene.ConclusionsThe research findings indicate that the proposed structure can reduce the normalized mode field area to 2.77×10⁻⁴, which is more conducive to photon integration and achieves better transmission performance. In addition, the crosstalk of two hybrid plasma waveguides, i.e., the minimum critical value of the center distance between waveguides without crosstalk, are reduced to 22 μm. These results contribute to a deeper understanding of characteristics graphene-dielectric hybrid plasmonic waveguide, which provide important references for the design and optimization ultra-low crosstalk hybrid plasma waveguides. The proposed structure will have broad development prospects in future terahertz integrated circuits.