Transient gratings in the transparent nanoliquid

In a gradient light field the nanoparticles in the transparent medium are controlled by the electrostrictive forces, causing changes in their concentrations. The medium is characterized by a cubic nonlinearity in this case that is correct only for small intensities of radiation. For large radiation intensities the potential energy of particle is more than heat one and it requires consideration of non-linearity of the highest order. In this paper the theoretical analysis of the light induced mass transport in the dispersed liquid medium is carried out for large intensities of radiation, when the change in concentration is greater than or comparable to the primary. It is shown the recording of the grating is a non-linear process and the phase grating becomes non sinusoidal. The amplitudes of the first harmonics increases in this case with the intensity of the light at the non-linear regime making possible the significantly increasing of the efficiency of holograms recording. We define the thermal nonlinearity in transparent nanosuspension occurred due to the heat when an electrostrictive stream of particles flows in a viscous fluid.