Simultaneous and Ultrasensitive Measurement of Refractive Index and Temperature Based on SPR of Hollow-Core Anti-resonant Fibers

A sensor on the basis of the surface plasmon resonance (SPR) of hollow core anti-resonant fiber (HC-ARF) with an alternating distribution of cladding tubes is proposed to realize concurrent detection of refractive index (RI) and the temperature. Two cladding tubes are plated with gold wire and silver layer inside, respectively. The liquid analyte is packed into the core of the fiber, and the silver layer is filled with liquid toluene which has a negative thermo-optical factor, thus forming a two-parameter detection channel for the RI and the temperature. The sensitivity crossover is resolved by using a dual wavelength matrix method. The outcome indicates that the optimum sensitivity of RI detection from 1.4850 to 1.5550 is up to - 55,000 nm/RIU, and the optimum sensitivity of temperature detection between - 20.0 and 40.0 degrees C is up to - 85 nm/degrees C. The figure of merit (FOM) of 625 RIU-1 can be achieved with RI of 1.5000 and the temperature of 20.0 degrees C. Comparison with other reported sensors demonstrates that our sensor has novel and simple fiber structure, ultrahigh sensitivity, and broad measurement range, which has an extensive prospect of application in dual-parameter detection that provide solid support for sensing area.