This article is cited in 13 papers

Nonlinear optical phenomena and devices

Nonlinear refraction of silver hydrosols during their aggregation

S. V. Karpov^a, M. K. Kodirov^b, A. I. Ryasnyansky^b, V. V. Slabko<sup>c

a</sup> L. V. Kirensky Institute of Physics, Siberian Branch of the Russian Academy of Sciences, Krasnoyarsk
^b Samarkand State University
^c Krasnoyarsk State Technical University

Abstract: The relation between the degree of aggregation of silver hydrosols and their nonlinear refractive index n₂ is studied experimentally. It is found that the sign of n₂ at a wavelength of 1.064 μm changes with increasing the aggregation degree, which corresponds to the replacing of self-focusing by self-defocusing. The observed effects are explained based on the analysis of a change in nonlinear dispersion of the medium, taking into account the interaction between phases and the photochromic effects, which are typical for colloidal structures with fractal geometry. It is shown that the change in the sign of the nonlinear refractive index of hydrosols upon irradiation by laser pulses of duration of less than 10^-7 s is caused by the perturbation of resonances of silver and water and by the competition between Kerr nonlinear polarisations involving these resonances.

PACS: 82.70.Gg, 81.07.-b, 42.65.Jx

Received: 28.06.2001

 English version: Quantum Electronics, 2001, 31:10, 904–908

Bibliographic databases:

•