Fiber semi-film SPR curvature sensor with the function of directional recognition

Abstract

We propose and demonstrate a fiber surface plasmon resonance (SPR) curvature sensor with the function of directional recognition by coating a metal film on one side of the fiber. By mathematical modeling, the relationship between the reflection angle (SPR incident angle) and bending radius is investigated. Functional testing of the sensing probe with a semi-film is performed. Simulating and testing results indicate that with the increases of the curvature, the resonance wavelength can be tested red shifts when the sensing probe is bent with a convex sensing film, and blue shifts when the sensing probe is bent with a concave sensing film, the depth of the resonance valley can be detected increases. Analysis shows that the testing results have a good agreement with the simulating results. The proposed fiber SPR sensor has the advantages of large curvature sensing range, directional recognition and good strength, which has strong application value.

Keywords

• Fiber SPR curvature sensor
• Semi-film
• SPR incident angle
• Directional recognition