The electrostrictive mechanism of optical nonlinearity in the artificial Kerr-like medium is analyzed. The recording of the dynamic hologram is significantly non-linear process at high intensities of radiation. It is shown that the nonlinear differential equation for a nanosuspension can be reduced to a Hamiltonian system of equations. The exact solution can be obtained for the nonlinear problem in disregard of the diffusion. The calculation gives expression for the space and time dependence of the concentration profile of the nanosuspension, which is valid at short times.
The electrostrictive mechanism of optical nonlinearity in the artificial Kerr-like medium is analyzed. The recording of the dynamic hologram is significantly non-linear process at high intensities of radiation. The model of the nonideal gas of nanoparticles includes the second virial coefficient only and allows the exact solution of the nonlinear equation. The amplitude of phase grating depends exponentially versus intensity but it saturates at the high filling factor due to the repulsion effect.
The theoretical analysis of the dynamic holograms efficiency in the transparent nanosuspension is carried out. It was compared the two-wave scheme of the dynamic holography and the four-wave mixing method. The mechanism of optical nonlinearity of the medium is due to the forces operating on the particles of the dispersed phase in light field (electrostrictive nonlinearity). The peculiarities of the kinetics of the both nonlinear processes were discussed. The results are relevant for dynamic holography in the nanosuspension, as well as for optical diagnostics of such media.
It was analyzed the self-focusing regime of the Gaussian beam in the nanosuspension with electrostrictive nonlinearity. The theoretical analysis of the light-induced mass transfer in the nanosuspension was carried out for large intensities of the Gaussian beam radiation, when the concentration change is comparable to the primary. The nonlinear lens in this mode is the exponential function of the incident light intensity. It is shown that the critical power value decreases significantly for high intensity beam. The results are relevant to the study of the radiation self-action in the nanosuspension and optical diagnostics of such materials.
The theoretical analysis of the dynamic holograms efficiency in the dispersion liquid medium is carried out. The mechanism of optical nonlinearity of the medium is due to the forces operating on the particles of the dispersed phase in light field. The summary nonlinear response of the nanosuspension includes two concentration mechanisms (electrostrictive and thermo-diffusive) and two thermal ones (light absorbing and particles drift caused by light pressure). The results are relevant for dynamic holography in the nanosuspensions, as well as for optical diagnostics of such media and thermo-optics spectrometry.
In this paper the theoretical analysis of the light-induced mass transfer in the dispersed liquid medium was carried out for large intensities of the Gaussian beam radiation, when the concentration is greater than or comparable to the primary. The non-linear lens in this mode increases exponentially with the intensity of the light. The results are relevant in the study of the radiation self-action in dispersed liquid media, as well as optical diagnostics of such materials, including the thermo-spectroscopy.
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.
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