High sensitivity concave-shaped photonic crystal fiber sensor based on surface plasmon resonance

A novel concave-shaped photonic crystal fiber sensor with double loss peaks based on surface plasmon resonance is proposed, whose properties are investigated by the finite element method. Gold can be utilized to generate excitation between the core mode and surface plasmon polariton mode. The simulation results indicate that in the wavelength range of 1.2 to 2.2 μm, the proposed sensor could detect the refractive index (RI) in the range of 1.18–1.30, the wavelength sensitivity of the primary loss peak could reach up to 18 000 nm/RIU and the corresponding resolution is 5.56 × 10−6 RIU in the RI range from 1.26 to 1.27. In addition, the double loss peaks could improve the detection accuracy, and the trough wavelength variation range is small, indicating that the proposed sensor is relatively stable, which improves the practicability of the sensor. This work could have a wide application value in the detection of medical testing, biomolecules, and organic chemistry.