High-sensitivity plasmonic temperature sensor based on photonic crystal fiber coated with nanoscale gold film

We demonstrate a photonic crystal fiber temperature sensor based on surface plasmon resonance and evaluate it using the finite element method. A temperature-sensitive material is injected into the central air hole of the photonic crystal fiber. The air hole is coated with nanoscale gold film. Six cores are formed by removing air holes in the second layer, which supports the core mode. The coupling between the core mode and the surface plasmon polariton mode occurs as the phase matching condition is satisfied. The average sensitivity and linearity become −2.15 nm/°C and 0.99991, respectively. The length of this fiber is only 1 mm. Our temperature sensor is competitive within the temperature sensor field.