Fig. 1. Schematic of device structure

Fig. 2. Reflectivity as a function of r, h, p, θ, and wavelength. (a) Reflectivity versus r when h=30 nm, p=600 nm, and θ=45°; (b) reflectivity versus h when r=70 nm, p=600 nm, and θ=45°;(c) reflectivity versus p when r=70 nm, h=30 nm, and θ=45°;(d) reflectivity versus θ when r=70 nm, h=30 nm, and p=650 nm

Fig. 3. Cross-section of device and magnetic field H distributions under different structural parameters. (a) Cross-section of xoz plane of device when r=100 nm; (b) SPP mode;(c) LSPR mode; (d) coupling mode when r=70 nm

Fig. 4. TMOKE as a function of r, h, p, θ, and wavelength. (a) TMOKE versus r when h=30 nm, p=600 nm, and θ=45°; (b) TMOKE versus h when r=70 nm, p=600 nm, and θ=45°;(c) TMOKE versus p when r=70 nm, h=30 nm, and θ=45°; (d) TMOKE versus θ when r=70 nm, h=30 nm, and p=650 nm

Fig. 5. Refractive index sensing performance of the device. (a) Change of TMOKE at different refractive indexes; (b) change of peak position at different refractive indexes

Table 1. Line width and FoM of sensing signal of the device at different refractive indexes