Refractive index detection via magneto-optical Goos-Hänchen effect in multilayer structure containing magnetic film

Refractive index detection based on magneto optical Goos-Hänchen (MOGH) effect is proposed in a prism-waveguide coupling structure. Double metal layers are adopted to enhance the MOGH effect. MO transfer matrix method is utilized to calculate the reflectivity of the waveguide. The influences of metal material and thickness are analyzed based on simulation results. Calculation results show the second metal layer determines the MOGH shift distribution in angular spectrum. Based on field distributions in the prism-waveguide coupling structure with symmetric and asymmetric metal layers, we choose asymmetric metal layers in the refractive index sensing model to realize higher sensitivity. A maximum sensitivity of 16.7 mm/RIU can be achieved based on the MOGH effect in the prism-waveguide coupling structure.