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
\(n_{\rm MF}\)
increases gradually when H//Light, while decreases when H
\(\bot \)
Light. The effect of temperature on
\(n_{\rm MF}\)
is relatively insignificant with the sensitivity of
\(-8\times 10^{\mathrm {-5}}\)
/°C. In addition, the mechanism is analyzed from the point of the microstructure by the Monte Carlo method.