The effect of nonlinear polarization rotation of elliptically polarized laser pulses in solutions of fullerene (C<sub>70</sub>)
in organic solvents and their mixtures has been experimentally studied. The nonlinear refractive index n<sub>2</sub> and nonlinear
cubic susceptibility Reχ<sup>(3)</sup> (ω;ω,ω,-ω) of these solutions have been defined. The correlation between the process of C<sub>70</sub> cluster formation in solutions and the angle of self-induced polarization rotation of passing laser beam was demonstrated. The physical mechanism of self-induced optical activity in solutions is discussed.
The laser induced nonlinear polarization rotation effect in a solution of Glycine has been investigated. The experimental data on polarization rotation of the laser beam are presented and have been used to determine of the third- order molecular susceptibility for the process of interest.
Rubidium vapor (10<SUP>11</SUP> - 10<SUP>14</SUP> cm<SUP>-3</SUP>) was irradiated by a dye-laser beam (10 kW(DOT)cm<SUP>-2</SUP> - 2 MW(DOT)cm<SUP>-2</SUP>, pulse duration approximately 30 nsec, linewidth <EQ 0.25 cm<SUP>-1</SUP>), which was tuned to the D<SUB>1,2</SUB>-resonance lines. The mutual competition of the two photon ionization, associative ionization and Penning ionization of the laser excited rubidium atoms was investigated. The data of laser intensities and a rubidium vapor concentrations, which results in domination of the each ionization channels were founded. On the basis of the received experimental results, the cross-section values for the multiphoton and collisional ionization channels of laser-excited atoms were determined.