Surface plasmon resonance sensor based on a D-shaped hollow microstructured fiber with bimetallic film

A surface plasmon resonance (SPR) sensor based on D-shaped hollow microstructured fiber with Au/ITO bimetallic film is proposed. The employment of bimetallic films improves the adhesion between optical films and fiber surfaces and further enhances the coupling effect of SPR. The effects of various structural parameters (e.g., sizes of air holes in the core and metallic film thickness) on the sensor performances are investigated with the finite element method. The maximum wavelength sensitivity of 9900 nm/RIU (RIU: refractive index unit) in the refractive index (RI) range of 1.30–1.39 is achieved, corresponding to a resolution of 1.01×10 −5 RIU −1 . The proposed SPR sensor also exhibits a maximum amplitude sensitivity of 425.58RIU −1 . These results demonstrate that the proposed D-shaped hollow microstructured fiber with the bimetallic film is a promising structure for refractive index sensing and may help design susceptible SPR fiber sensors.