Dual-parameter sensor for simultaneously measuring refractive index and temperature based on no-core fiber and SPR effect

Abstract

Refractive index and temperature are two basic properties of matter. Therefore, we propose a dual-parameter sensor based on no-core fiber and surface plasmon resonance (SPR). It can simultaneously measure temperature and refractive index. The sensor structure comprises no-core fiber, metal silver, and polydimethylsiloxane (PDMS). Metallic silver is used to excite the SPR effect, and PDMS is a suitable temperature-sensitive material. The silver film is deposited on the bottom of no-core fiber for refractive index measurement. Silver film and PDMS are deposited on the top of no-core fiber for temperature measurement. Numerical results show that refractive index and temperature can be reflected in the same spectrum, and the two parameters do not interfere with each other. This phenomenon improves the efficiency of measurement. In addition, the maximum spectral sensitivities of the sensors are 5200 nm/RIU and 7.2 nm/℃, respectively. The results also show that the sensor's performance is not sensitive to the change in structural parameters, which makes the sensor easy to prepare. Dual parameter measurement and simple structure make the sensor unique. It has good application prospects in biochemical detection, environmental monitoring, medical sensing, and other fields.