An Optoacoustic Method for Analyzing Spatial Inhomogeneity of Light Extinction and Its Time Variations in Diluted Magnetic Fluids

It has been shown that the laser optico-acoustic method can be used to study time variations in the light extinction coefficient of magnetic fluids. Diluted aqueous magnetic fluids with different concentrations of magnetite particles have been used as the objects of investigation. The dependence of the time shape of the leading edge of the optico-acoustic signal excited in an examined fluid on its optical properties enables one to measure the light extinction coefficient and restore its spatial distribution over the fluid depth. It has been experimentally shown that the light extinction coefficient of a diluted magnetic fluid decreases with time due to structural changes occurring in the fluid.