The technique expanding the validity of single-beam Z-scan method for measurement of nonlinear-optical properties of various media based on paraxial approximation was developed. The comparison of various methods of nonlinear susceptibilities measurement interpretation was carried out. The agreement between values of nonlinear-optical parameters measured in extended and thin media was obtained.
It has been shown, that usage of the certain initial phase modulation of fundamental laser pulses is capable to result in
increase of pulse compression efficiency in type II second harmonic generation. The variations ofinitial phase
modulation of the fundamental laser pulses expand optimal ranges ofthe nonlinear medium and laser radiation
parameters needed for efficient pulse compression.
The values of tensor components of nonlinear susceptibilities responsible for self-action effects have been measured in quadratic nonlinear-optical crystals at the Nd:YAG laser wavelength. The angular dependences of the nonlinear susceptibilities have been determined on the base of measured relations between tensor components. The variation of the high-order nonlinear susceptibilities at various spectral ranges has been discussed. The measurements have been conducted on the basis of the analysis of polarization dependences of focused radiation transmittance in the Z-scan scheme.
The measurements of nonlinear refractive indices and third-order susceptibilities responsible for self-action effects in nonlinear-optical crystals (KDP, KTP, BBO, LiNbO3) in various spectral ranges (1064 and 532 nm) were carried out by the Z-scan method. It was obtained that investigated media (excepting KTP crystal λ=1064 nm) had self-focusing properties. The significant values of nonlinear losses were recorded at λ=532 nm. The analysis and comparison of experimentally and theoretically obtained values of nonlinear susceptibilities are given. The angular and polarization dependencies of Kerr nonlinearities were analyzed.
It is shown, that influence of self-action effects is capable to expand a spectral range of resonant optical harmonic generation and in three-photon resonant medium with positive dispersion under tight focusing the influence of ac Shtark shift results in fourth-order power dependence of third harmonic efficiency on fundamental intensity and medium density. The comparison with known experimental data is carried out.
Influence of relation between scattering matrix elements responsible for Stokes and anti-Stokes pulse amplification on efficiency of the energy exchange and character of self- induced amplitude-phase modulation is analyzed in the essentially transient regime.
The powerful tunable laser with high output energy is needed for laser spectroscopy, laser chemistry, biology, medicine and other appi icat ion. The result of design of the powerful Nd: glass laser set -up ut ii iz ing process of harmonic generation, optical parametric oscillation, parametric ampl if icat ion under the injection of the seeding radiat, st iinulated Raman scattering all owing to span completely through the spectral range from 1.3 to 0. with the output energy of several J are reported.
The nonlinear optical properties of a metal irradiated by a high power laser radiation are theoretically analyzed. It is shown that in the radiation field the deflection of the distribution function from the equilibrium one leads to sharp relative increase of the image part of the nonlinear current and, hence, to the nonlinear optical response of the surface.