Refractive Index and Temperature Sensing Based on Surface Plasmon Resonance and Directional Resonance Coupling in a PCF

We propose a refractive index (RI) and temperature sensor design based on hybrid mechanisms in a D-shaped all-solid photonic crystal fiber. The D-shaped flat surface is coated with a silver film to construct surface plasmon resonance for the RI sensing, while a single hole in the all-solid structure is filled with benzene to form a directional resonance coupling for the temperature sensing. With a strong coupling between the core mode and the resonance modes, the maximum sensitivities of the RI and the temperature are as high as 12900 nm/RIU and 23.85 nm/°C. Since two resonance designs are used, this sensor can avoid the need for metal coating in the fiber holes and use a high RI sensing medium for temperature sensing.