▎ 摘　　要

A novel configuration of dynamically tunable surface plasmon polaritons (SPPs) is proposed based on two waveguides and one nanotube graphene in the terahertz range and is numerically investigated as a highly sensitive sensor. In the proposed structure, the two graphene waveguides coupled to the nanotube have two plasmonic modes which have two high sensitivities in different frequencies. The results show that in this structure, the sensitivity values are measured as the order of 7714 nm/RIU inside the tube and 18500 nm/RIU in the total environment. The sensitivity value in the total environment is at least 148.3% larger than those of previously reported waveguides which is an excellent result. This graphene waveguide sensor can have an important practical application in biosensors and lab-on-chip systems.