Fig. 1. Micrographs of a sensor. (a)-(e) Micrographs of the cut induced SRRs with the asymmetric factor g=0, 5, 9, 13, 17 μm;(f) schematic of the cut-induced SRR structure

Fig. 2. Transmission spectra of the cut-induced SRR sensor at different degrees of asymmetry

Fig. 3. Influence of parameter a and parameter w on dual-band resonant peak of a sensor. (a) a; (b) w

Fig. 4. Surface current distribution of the cut-induced SRR sensor at g=5, 9 μm

Fig. 5. Simulation and fitting of the cut-induced SRR sensors. (a)-(d) CST software simulation diagram; (e)-(h) fitting diagram of the coupled resonance model

Fig. 6. Coupling strength Ω at different asymmetry degree g

Fig. 7. Electric field diagrams of the cut-induced SRR sensor at g=5, 17 μm

Fig. 8. Transmission spectra of hyaluronic acid with different mass concentrations, inset is the hyaluronic acid sample

Fig. 9. Dependence of resonance peak shift on hyaluronic acid solution with different mass concentrations. (a) Fano resonance;(b) dipole resonance

Fig. 10. Relationship between the peak intensity of the resonance peak and mass concentration of hyaluronic acid, the five-pointed star is the amplitude value of the resonance peak in the experimental data in Fig.8. (a) Fano resonance; (b) dipole resonance