UDC 535.21:547We have experimentally studied for the first time the effect of photoinduced rotation of the plane of polarization for pulsed laser radiation in solutions of C 70 fullerene in organic solvents and their mixtures. We have shown that the effect is observed for elliptical polarization of the laser radiation and is absent for linear polarization. We present the results of a study of the nonlinear optical characteristics of the C 70 solutions. We discuss the physical mechanisms by which nonlinear gyrotropy is induced in solutions.Introduction. Study of the optical and nonlinear optical properties of nanocarbon materials, in particular fullerenes and carbon nanotubes of various modifications, is of significant interest in connection with the possibility of their practical use in designing the next generation of fast optical and nonlinear optical devices. A number of publications (see, for example, [1][2][3][4][5]) have reported the use of solutions of C n fullerenes (n = 60, 70, 76, 84) and fullerenecontaining films as nonlinear optical limiters for laser radiation. In [6], Q-switched and self-mode-locked conditions were realized in a pulsed Er 3+ glass laser (λ = 1.54 μm) using a passive gate based on solutions of single-walled carb-

The dynamics of pulse trains formation in a cavity of Nd:YAG laser with passive dye-activated thin film and nonlinear negative feedback was studied. The maximum duration of extended pulse trains (6.5 µs) was experimentally achieved.