Theoretical analysis of a dual-channel surface plasmon resonance sensor for the detection of liquid temperature and refractive index

Abstract A novel dual-D photonic crystal fiber utilizing surface plasmon resonance is introduced for the simultaneous detection of the liquid’s refractive index (RI) and temperature. One channel is designed with a gold coating to assess the RI of the liquid, whereas the other channel includes a gold layer along with polydimethylsiloxane for tracking temperature changes. The design incorporates two distinct channels along with structural asymmetry, effectively addressing the issue of sensor cross-sensitivity. To explore the sensor’s characteristics, a combination of finite element method and numerical analysis was employed. The results show that the wavelength sensitivity reaches 2000 nm RIU −1 within the RI range of 1.31–1.36 for liquids, while temperature sensitivity is recorded at −0.31 nm °C -1 across a broad temperature spectrum from −25 °C to 150 °C. With analyte measurement channels designed for simplicity, and streamlined measurement and operation, this sensor offers a straightforward design, affordability, and real-time monitoring capabilities, making it a promising approach for multi-parameter detection in biological, medical, and industrial applications.