Magnetic field dependence of Cotton–Mouton rotation for magnetic fluid films

The azimuthal distribution of the transmitted intensity of a linearly polarized laser beam through a 6μm-thick magnetic fluid film was measured under various magnetic fields H normal to the direction of the light propagation to study the magnetic field dependent Cotton–Mouton (C–M) effect of the sample. Here, the azimuthal angle η is the angle between the transmission axes of the polarizer and the analyzer. For obtaining the most significant variation in the polarization of the incident light, the angle between H and the polarization of the incident light θ is set to be 45°. The I–η curves were found to be symmetric with relative maximum at ηI=max around 0° and minimum at ηI=min around 90°. Furthermore, these curves showed a gradual shift up to Δη=1.55° with respect to the curve under zero magnetic field as H increased to 250Oe. All the details will be discussed in this report.