Tunable Characteristics and Mechanism Analysis of the Magnetic Fluid Refractive Index With Applied Magnetic Field

The tunable refractive index of the magnetic fluid (MF) is a unique optical property, which has attracted a lot of research interest in recent years. In this paper, a method based on the Fresnel reflection at the fiber end face is presented. Experimental measurements are carried out to investigate the magnetic field (intensity and direction) and temperature-dependent refractive index of the MF. For a given concentration, with the increase of the magnetic field intensity, the nMF increases gradually when H//Light, while decreases when H⊥Light. The effect of temperature on nMF is relatively insignificant with the sensitivity of -8 × 10^-5/°C. In addition, the mechanism is analyzed from the point of the microstructure by the Monte Carlo method.