A modulation method of light-induced pseudo-prism in nanosuspension

In this paper, a modulation method for creating a pseudo-prism in a nanodispersed liquid-phase medium is proposed, based on using the light pressure of radiation. Usually, the pseudo-prism method is used to study a stationary sedimentation profile in a dispersed medium. For nanoparticles and macroscopic cell sizes, the typical equilibrium times are tens of hours. Even with significant light pressure forces that exceed gravitational pressures, the characteristic time of settling the sedimentation profile remains very long. Therefore, achieving an equilibrium distribution requires a long experiment, which places high demands on the stability of all conditions and is practically unrealizable due to the presence of convective flows. Modulation of the reference beam makes it possible to study the dynamics of the pseudo-prism at short times, which significantly increases the accuracy of the optical diagnostic method. The article presents a theoretical analysis of the process of light-induced mass transfer in a dispersed liquid-phase medium located in a homogeneous time-modulated light field. As a result of the analytical solution of the problem of light-induced mass transfer, an expression was obtained that makes it possible to determine the amplitude of the angle of deflection of the signal beam in a pseudo-prism.

pseudoprism method, light pressure, nanofluids, optical diagnostics, separation, nanoparticles