Research on photonic crystal fiber based on a surface plasmon resonance sensor with segmented silver-titanium dioxide film

A photonic crystal fiber based on a surface plasmon resonance sensor coated with segmented silver-titanium dioxide (${\rm Ag} \text{-} {{\rm TiO}_2}$Ag-TiO2) film is proposed for microfluid refractive index sensing. The sensing properties of the designed sensor are analyzed numerically by the full-vectorial finite element method. The results display that the wavelength sensitivity can be tuned by the thickness of the ${{\rm TiO}_2}$TiO2 film and segmented number and angle of the ${\rm Ag} \text{-} {{\rm TiO}_2}$Ag-TiO2 film. It is observed that an average sensitivity of 6329 nm/RIU for refractive indexes ranging from 1.330 to 1.360, and a maximum wavelength sensitivity of 10600 nm/RIU with a high wavelength resolution of ${9.43} \times {{10}^{ - 6}}\;{\rm RIU}$9.43×10−6RIU, can be achieved in the sensing range of 1.350 to 1.355. In addition, it also shows a maximum amplitude sensitivity of ${633.4001}\;{{\rm RIU}^{ - 1}}$633.4001RIU−1, and the maximum figure of merit is 303 with ${n_a}$na varying from 1.330 to 1.360, which can be applied to the field of chemical and biological analysis.