Fig. 1. Schematic diagram of the spectrometer.

Fig. 2. (a) Transmission curve of the drop port obtained using the FDTD method (blue solid line) and transfer matrix method (red dotted line). (b) Electric field distribution of the resonator at the resonant position (λ=2.2989  μm). (c, d) Electric field distribution of the cross section (white line in (b)) without and with single-layer graphene, respectively. The black rectangles in (c) and (d) represent the position of waveguide, and the orange dashed line in (d) represents the position of the single-layer graphene.

Fig. 3. Image part of the optical conductivity in the operation’s wavelength range.

Fig. 4. (a) Real part of the refractive index of graphene Re(nG) among different Fermi levels as a function of the incident light wavelength λ. (b) The effective refractive index with and without graphene. (c) The calculated transmission curve corresponding to the different effective refractive index curve in (b), and the red dotted line is the same as the dotted line in Fig. 2(a). The illustration of color line is suitable for all plots.

Fig. 5. Spectrometer spectrum (black and red line) and applied voltage (blue line) as a function of the incident light.