Fig. 1. Schematic diagram of spectral reconstruction based on spectral coding of metasurface. (a) Schematic diagram of spectral detection process; (b) MIM structure diagram (p is the period of unit structure); (c) fully connected neural network framework

Fig. 2. Design results of the metasurface unit structure. (a) Schematic diagram of unit structure with four cylinders and spectral transmittance corresponding to different w and r values; (b) a pixelated unit structure diagram and spectral transmittance under TE light and TM light irradiation, and the red five-pointed star line is the transmittance curve of substrate ZnSe; (c) correlation coefficients between 530 spectral transmittance curves; (d) average value of 530 spectral transmittance curves, and the red line indicates the threshold of transmittance of 50%

Fig. 3. Schematic diagrams of four selected channel structures and corresponding spectral transmittance curves. (a) Structure 1;

Fig. 4. Reconstruction results of wideband spectra. (a) Example 1; (b) example 2; (c) example 3; (d) example 4

Fig. 5. Spectral curve reconstruction results with single peak. (a) Example 1; (b) example 2; (c) example 3; (d) example 4