Fig. 1. Structure of single baffle MIM waveguide coupled cloud like cavity

Fig. 2. Formation process of Fano resonance. (a) Transmission spectrum of only resonant cavity or baffle; (b) Fano resonance line of single baffle MIM cloud like cavity

Fig. 3. Stable electric field distribution diagram of three resonance modes . (a) 637 nm; (b) 819 nm; (c) 1103 nm

Fig. 4. Effect of cavity width W₀ on Fano resonance peak

Fig. 5. Effect of resonant cavity width W₀ on FOM. (a) Effect of W₀ on FOM of mode 1 and mode 2; (b) effect of W₀ on FOM of mode 3

Fig. 6. Effect of separation distance k on Fano resonance peak

Fig. 7. Effect of separation distance k on FOM value. (a) Effect of k on FOM of mode 1 and mode 2; (b) effect of k on FOM of mode 3

Fig. 8. Effect of coupling distance g on Fano formant

Fig. 9. Effect of coupling distance g on FOM value. (a) Effect of g on FOM of mode 1 and mode 2; (b) effect of g on FOM of mode 3

Fig. 10. FOM values at different wavelengths after optimizing structural parameters

Fig. 11. Analysis of sensing characteristics. (a) Effect of ambient refractive index n on Fano resonance peak; (b) relationship between resonance wavelength and refractive index