Simultaneous measurement of temperature and humidity using a dual-parameter sensor based on SPR and no-core fiber technology

In this article, we present a surface plasmon resonance (SPR) sensor based on a no-core fiber (NCF) structure for simultaneous measurement of temperature and humidity. The sensor is simulated by depositing a silver film on the exterior of the NCF by magnetron sputtering, followed by the application of a composite thin film of polyvinyl alcohol (PVA) and polydimethylsiloxane (PDMS). This configuration induces SPR resonance phenomena at two distinct wavelengths, resulting in the splitting of the resonance peak into two distinct peaks, enabling simultaneous measurement of temperature and humidity. To achieve optimal sensor performance, the thickness of the PDMS-PVA composite film, the proportion of sensitive materials, the thickness of the silver film, and the structural parameters of the fiber were optimized. Simulation results show that the sensor exhibits a humidity sensitivity of 8.60 nm/%RH over a relative humidity (RH) range of 50%-100%. The highest temperature detection sensitivity achieved is 7.40 nm/°C. This sensor holds great potential for applications in monitoring changes in environmental temperature and humidity.