Fig. 1. Device block diagram

Fig. 2. Effect of super-cell structure and length of the top Ag nanostructure L on reflectivity and reflection phase

Fig. 3. Effect of relative position of grating transverse（Δ）on transmission spectrum

Fig. 4. Transmission spectra of gratings at different widths w₁ on this structure

Fig. 5. Transmission spectra of gratings with different heights h₁ on this structure

Fig. 6. Transmission spectra of this structure at different SiO₂ spacer heights t₁

Fig. 7. Forward and reverse transmission spectra of the device when an x-polarized state light wave is incident

Fig. 8. The electric field distribution of the structure at 1 550 nm when light is incident in the forward and reverse directions

Fig. 9. The electric field distribution of the structure at 1 128 nm when light is incident in the forward and reverse directions

Fig. 10. The reflectance，transmittance and absorption spectra and electric field distribution E_x at 1 300~1 400 nm band when x-polarized light wave is reverse incident

Fig. 11. Forward and reverse transmission spectra of the device when a light wave in the y-polarized state is incident

Fig. 12. Abnormal reflection phenomenon when y-polarized light waves are reverse incident at 920 nm