Polarization characteristics of nonlinear refraction and nonlinear scattering in several solvents

The polarization characteristics of nonlinear refraction and nonlinear scattering in several solvents (toluene, o-dichlorobenzene, N, N-dimethylformamide) are studied using the polarized light Z-scan technique with femtosecond laser pulses. For nonlinear refraction, the physical mechanism of the polarization characteristics is that the nonlinear polarization component related to Re(χxyyx(3)) could be adjusted by polarization state of incident lightin isotropic media. For nonlinear scattering, the polarization characteristic is related to the self-focusing effect, which depends on the nonlinear refractive index and polarization state of incident light. In addition, the values of nonlinear refractive indices and third-order nonlinear susceptibility components are determined for these solvents at the femtosecond time scale. Both nonresonant electronic nonlinearity and fast noninstantaneous nuclear nonlinearity contribute to these values at the pulse width used in the measurements. Also, these nonlinear refractive indices and third-order nonlinear susceptibility components could be used in calculating nonlinear optical parameters of those novel materials that need to be dissolved in these solvents in nonlinear optical measurements.