SPR fiber optic sensor for simultaneous temperature and humidity measurement using AuNPs

In this work, we design a fiber optic sensor that can simultaneously measure temperature and relative humidity based on surface plasmon resonance. One channel is coated with a gold film and carboxymethyl cellulose to detect relative humidity, while the other channel is coated with a gold film, gold nanoparticles, and polydimethylsiloxane to detect environmental temperature. The carboxymethyl cellulose coating is used to detect relative humidity by the change in refractive index caused by moisture absorption, while the gold nanoparticles not only improve the sensitivity of the sensor, but also affect the position of the surface plasmon resonance valley to better differentiate the resonance wavelengths of the two channels in the same spectrum. The polydimethylsiloxane coating is used for temperature sensing due to its refractive index sensitivity to temperature change. The simultaneous measurement of dual parameters of temperature and relative humidity has been successfully realized. It is simple in structure and easy to manufacture. It has broad application prospects in the fields of monitoring of living environment and food safety.