1：Experimental Design and Method Selection:

The study proposes a novel configuration of dynamically tunable surface plasmon polaritons (SPPs) based on two waveguides and one nanotube graphene in the terahertz range. The 3D finite element method (FEM) is employed to analyze the simulation results with a perfectly matched layer (PML) boundary condition used in all directions. The transverse magnetic (TM) mode is utilized to excite SPPs in this waveguide.

2：Sample Selection and Data Sources:

The proposed plasmonic graphene biosensor consists of two rolled-up SiO2 waveguides covered with graphene sheets coupled to the middle part of the nanotube. The material under sensing is at the center of the nanotube.

3：List of Experimental Equipment and Materials:

The thicknesses of the silicon and graphene layers are 50 and 1 nm, respectively, the radius of the nanotube is 320 nm, and the gap between the waveguides and the nanotube is 50 nm.

4：Experimental Procedures and Operational Workflow:

Light is incident from the lower waveguide and is detected through the upper waveguide. The effects of the refractive index, radius of the nanotube, gap between the waveguides and the nanotube, and chemical potential on the sensor's performance are investigated.

5：Data Analysis Methods:

The relationship between the refractive indices and the wavelength shift is analyzed to determine the sensor's sensitivity. The figure of merit is calculated as the ratio of sensitivity to full width at half maximum (FWHM).