Design and optimization of hexagonal SPR-based photonic crystal fiber magnetic field sensor with magnetic fluid infiltration.

A surface plasmon resonance (SPR)-based photonic crystal fiber (PCF) magnetic field sensor with hexagonal lattice is proposed. Magnetic fluid is injected into two air holes for magnetic field sensing. In order to obtain the optimal structure of magnetic field sensor, four types of hexagonal PCF models are discussed and compared. The influence of structure parameters d, d 1 , d 2 , t, D, and Λ on sensing characteristics is analyzed when the PCF-3 is determined. The maximum sensitivity and corresponding resolution can reach 1150 pm/Oe and 0.087 Oe, and figure of merit (FOM) is up to 0.0556/Oe in the magnetic range of 30–150 Oe. The maximum wavelength sensitivity is 25000 nm/RIU, when the range of refractive index (RI) is from 1.420 to 1.450. In addition, the temperature sensitivity is only 65 pm/K, indicating small temperature crosstalk. The proposed sensor has the advantages of large FOM, good linearity and simple structure, enabling accurate measurement of magnetic field, especially suitable for weak magnetic field detection. Good performance makes it applicable to industrial production, military affairs, health and environmental monitoring. [ABSTRACT FROM AUTHOR]