Fig. 1. Schematic of designed structure (the symbol P refers coupling prism. G and L denote gain and loss resonators, respectively. A denotes air layers. A₁ is coupling layer that is full of detected material. The prism has a base angle θ＝30°. The light incident direction is perpendicular to external interface of the prism)

Fig. 2. Transmission spectrum at τ＝0

Fig. 3. Transmission spectra as the value of τ gradually increases

Fig. 4. Relationship between blood glucose mass concentration and its refractive index

Fig. 5. Transmission spectra corresponding to different blood glucose mass concentrations

Fig. 6. Dependence of transmittance on blood glucose mass concentration with the fixed frequency

Fig. 7. Calculation of sensor sensitivity. (a) Calculation method of relative sensitivity; (b) sensitivity corresponding to incident wave frequency of 1466.508 THz

Fig. 8. Sensitivity of sensor at different incident wave frequencies

Fig. 9. Transmission spectrum and sensitivity curve of peak value sensing. (a) Transmission spectrum; (b) sensitivity curve

Fig. 10. Original data and fitting curve