Fig. 1. Schematic of coupled semi-circular resonant cavity

Fig. 2. Transmission spectrum of coupled semi-circular resonant cavity system. (a) Single baffle and single semi-circular cavity; (b) baffle and semi-circular cavity exist at the same

Fig. 3. Normalized magnetic field distribution of semi-circular resonant cavity structure at different wavelengths. (a) λ=794 nm; (b) λ=852 nm; (c) λ=1100 nm; (d) λ=1150 nm

Fig. 4. Influence of semi-circular radius R on transmission spectra and FOM. (a) Transmittance spectrum corresponding to different values of R; (b) relationship between resonance wavelength distribution of transmission spectrum and R; (c) FOM values corresponding to different R values

Fig. 5. Influence of semi-circular thickness d on transmission spectra and FOM. (a) Transmittance spectrum corresponding to different values of d; (b) relationship between resonance wavelength distribution of transmission spectrum and d; (c) FOM values corresponding to different d values

Fig. 6. Influence of coupling distance g on transmission spectra and FOM. (a) Transmittance spectrum corresponding to different values of g; (b) FOM values corresponding to different g values of two modes

Fig. 7. Optimized FOM values of two modes. (a) FOM1 optimal; (b) FOM2 optimal

Fig. 8. Influence of medium refractive index n on transmission spectra. (a) Transmittance spectra corresponding to different values of n; (b) relationship between resonance wavelength of transmission spectrum and refractive index n