Incident-power-dependent optical transmission properties of magnetic fluid films

Incident power has an important effect on the optical transmission properties of magnetic fluids. Difference in the effect of the incident power on the optical transmission properties with and without an applied magnetic field was investigated by measuring the transmitted power of the incident light through the magnetic fluid film. In the absence of an applied magnetic field, an approximately linear relationship exists between the incident power and the transmitted power of magnetic fluid films, but the relationship is nonlinear when a magnetic field is applied. Moreover, variation in the optical transmission properties under a magnetic field with various incident powers was measured in experiment. As the magnetic field is enhanced, the transmitted power of the magnetic fluid film first decreases, then increases, and finally reaches saturation. The magnitude of the change in the transmitted power, and the magnetic field range correspond to decreases, increases and saturation are related to the incident power. Therefore, for the sensing applications, depending on the measuring range of the magnetic field and the required variation range of the transmitted power, magnetic fluid film sensors exhibit different characteristics if different incident power values are selected.