Theoretical analysis of a highly sensitive SPR temperature sensor based on Ag/TiO2 hyperbolic metamaterials and PDMS film

• The resonance wavelength can be tuned to longer wavelength that corresponds to higher temperature sensitivity and obtains better DSD-FOM by adjusting the parameters of the HMMs. • Under the same conditions, the temperature sensitivity of the HMMs-SPR sensor is 4 times of Ag-SPR sensor, and the average DSD-FOM is 6 times than that. We proposed and theoretically investigated a highly sensitive surface plasmon resonance (SPR) temperature sensor. The sensor is composed of a tapered no-core fiber (TNCF) deposited with hyperbolic metamaterials (HMMs) and a layer of polydimethylsiloxane (PDMS). The resonance wavelength can be tuned to longer wavelength that corresponds to higher temperature sensitivity and obtains a better product of depth of dip and figure of merit (DSD-FOM) by adjusting the parameters of the HMMs. The PDMS coated on the surface of the HMMs can further improve the temperature sensitivity due to its high thermal-optic coefficient. Simulation results show that the optimized temperature sensitivity can reach −16.26 nm/°C at 20 °C, and has an average DSD-FOM of 0.221 °C −1 in the range of 20 °C–70 °C, which is several times higher than that of Ag-SPR sensor.