Fig. 1. Schematic diagram of oblique symmetric double rectangular ring filter structure

Fig. 2. Transmission spectra of single rectangular ring and oblique symmetric double rectangular ring structure filters

Fig. 3. Magnetic field distribution diagram of single rectangular ring (λ₁) and oblique symmetric double rectangular ring (λ₂) structural filters. (a) λ₁=600 nm; (b) λ₁=650 nm; (c) λ₁=850 nm; (d) λ₁=1400 nm; (e) λ₂=600 nm; (f) λ₂=680 nm; (g) λ₂=850 nm; (h) λ₂=1400 nm

Fig. 4. Effect of changing parameters L and H on transmission spectra of filter. (a) Transmission spectra with different L; (b) transmission spectra with different H

Fig. 5. Effect of changing parameters l and d on transmission spectra of filter. (a) Transmission spectra with different l; (b) transmission spectra with different d

Fig. 6. Transmission spectra of optimized structures with three different parameter combinations

Fig. 7. Spectra distribution of three different refractive index media

Fig. 8. Schematic diagram of improved structure of oblique symmetric double rectangular ring structure filter with baffle

Fig. 9. Schematic diagram of electrode position

Fig. 10. Spectra of optimized structure of oblique symmetric double rectangular ring structure filter with baffle. (a) Transmission spectrum of optimized structure when U=0; (b) transmission spectra of optimized structures under three different applied voltages