Fig. 1. Schematics of multilayer film grating structure. (a) 3D diagram of hybrid multilayer film grating structure; (b) cross-sectional view of hybrid multilayer film grating structure and optical modes in the structure

Fig. 2. Simulation results of multilayer film gratings. (a) Transmission spectra of TiO₂ grating and multilayer film grating; (b) electric field distribution at the like-GMR peak; (c) electric field distribution at the central wavelength of multilayer film

Fig. 3. Simulation results of multilayer grating after introducing defect layer. (a) Transmission spectra of multilayer grating; (b) transmission spectra under different thicknesses of defect layers in multilayer gratings with N=7; (c) electric field distribution at like-GMR

Fig. 4. Simulation results of multilayer grating with N=5. (a) Transmission spectra at different central wavelengths; (b) formation process of resonance-coupled BIC; (c) Q-factor in the central wavelength range of 550‒700 nm; (d) Q-factor at different incident angles

Fig. 5. Simulation results of multilayer film gratings under different structure parameters. (a) Formation process of resonance-coupled BIC with P=400 nm; (b) relationship between the central wavelength/BIC wavelength and the period; (c) Q-factor of multilayer grating with different periods; (d) BIC wavelengths, central wavelengths, and Q-factor of multilayer grating for different materials