Origin and applications of magnetically tunable refractive indexof magnetic fluid films

Abstract

When an external field was applied, the refractive index of the magnetic fluid film was observed to be modulated as the field exceeded a critical strength. We found that the stronger the magnetic field, the higher the refractive index. By taking both the formation of the columns and the variation in the concentration of the liquid phase in magnetic fluid films under external magnetic fields into account, the refractive index was calculated and compared with experimental data. When we did this, we noticed a consistency that implies that the phase separation leads to the variation in the refractive index of the magnetic fluid film as the magnetic field strength is changed. With such a property as a tunable refractive index, the feasibility of using a magnetic fluid in a tunable optical device is worthy of investigation.

Multidimensional microstructured photonic device based on all-solid waveguide array fiber and magnetic fluid

“…When the magnetic field intensity is more than 300 Oe, the transmission loss gradually becomes constant again because of the saturated magnetization of the MF. This phenomenon could be explained by the RI of the MF and the magnetic field intensity satisfying the Langvin function [35]. When an external magnetic field is applied, the magnetic particles dispersed evenly in the MF would agglomerate to form magnetic columns.…”

Optical Current Sensors for High Power Systems: A Review

“…When the magnetic field strength was raised more columns were formed leading to a decrease in the optical transmission. Later on, the same group investigated the refractive index of the magnetic fluid film and founded to be magnetically modulated in the presence of an external magnetic field [76,77].…”

Tunable photonic crystals based on MnFe2O4 magnetic fluids by magnetic fields

“…The index contrast between the solid phase (the ordered structure) and the liquid phase (the remanent magnetic fluid in reduced concentration) is given by [18,19] where the first term in the right hand (n sol ) is the refractive index of the solid phase and the second term is the refractive index of the liquid phase which is derived from the theory of effective dielectric constant of two-phase system. The parameter f is given as…”