Fig. 1. (a) Three-dimensional schematic diagram and (b) two-dimensional structure diagram of slotted waveguide coupled structure

Fig. 2. Transmission spectrum of slotted waveguide coupled structure by simulation

Fig. 3. Simulation of magnetic field spatial distribution of slotted waveguide coupled structure at(a) 500 nm (mode 1) , (b) 625 nm (mode 2) , (c) 725 nm (mode 3) and (d) 600 nm (propagation forbidden) by FDTD

Fig. 4. (a) Transmission spectrum and (b) transmission peak-wavelength relation with different W(W_c = 250 nm, L = 600 nm, d = 10 nm, L_d= 0 nm)

Fig. 5. (a) Transmission spectrum and (b) transmission peak-wavelength relation with different L_d(W_c = 250 nm, L = 600 nm, d = 10 nm, W₁ =W₂=100 nm)

Fig. 6. (a) Transmission spectrum and (b) transmission peak-wavelength relation with different W and L_d(W_c = 250 nm, L = 600 nm, d = 10 nm)

Fig. 7. (a) Transmission spectrum and (b) transmission peak-wavelength relation with different W_c(W = 120 nm, L = 600 nm, d = 10 nm)

Fig. 8. (a) Transmission spectrum and (b) magnetic field distribution of mode 1-4 with W_c = 450 nm