Fig. 1. Schematic of Ag nano pit-silicon grating composite microstructure. (a) Ag nano-pit embedded in silicon grating gap; (b) Ag nano-pit embedded in silicon grating gap and grating column surface; (c) three-dimensional structure view of Ag nano-pit embedded in silicon grating gap

Fig. 2. Spectral characteristics of bare silicon materials in near infrared band

Fig. 3. Spectral characteristics of silicon grating structure when cycle and height change simultaneously. (a) Absorption; (b) reflection; (c) transmission

Fig. 4. Spectral characteristics of silicon grating structure when duty cycle changes

Fig. 5. Changes of near-infrared absorptivity of silicon grating embedded in Ag nano-pit

Fig. 6. SPP wavelength excited by different interfaces of silicon grating composite structure

Fig. 7. x-z cross-sectional view of adding Al₂O₃ dielectric layer

Fig. 8. Effect of dielectric environment on near-infrared absorptivity of Ag nano pit-silicon grating composite structure

Fig. 9. Intensity distribution on different structure surfaces. (a) Silicon grating gap; (b) Ag nano-pit embedded in silicon grating gap; (c) Ag nano-pit embedded in silicon grating gap and column surface