The optical limiting properties of alloyed CdZnS quantum dots associated with erythrosine dye are analyzed using 532 nm, 40 ps pulses. We show that joint influence of saturable absorption, reverse saturable absorption and two-photon absorption cause the optical limiting of 532 nm radiation at the pulse energies exceeding 1 mJ. The nonlinear refraction and nonlinear absorption of these quantum dots associated with different organic dyes were studied using 1064 nm and 532 nm radiation. The nonlinear refraction index and nonlinear absorption coefficient of CdZnS quantum dots were measured at λ = 1064 nm to be 2 × 10 cm W and 1.2 × 10 cm W, while the reverse saturable absorption of CdZnS quantum dots and erythrosine at λ = 532 nm was almost two orders larger. The potential applications of these quantum dots for high-order harmonic generation are discussed.

We demonstrate the technique allowing the fine tuning of the distance between the laser-produced plasma plumes on the surfaces of different materials, as well as the variation of the sizes of these plumes. The modification of plasma formations is based on the tilting of the multi-slit mask placed between the heating laser beam and target surface, as well as the positioning of this mask in the telescope placed on the path of heating radiation. The modulated plasma plumes with the sizes of single plume ranging between 0.1 and 1 mm were produced on the manganese and silver targets. Modification of the geometrical parameters of plasma plumes proved to be useful for the fine tuning of the quasi-phase-matched high-order harmonics generated in such structures during propagation of the ultrashort laser pulses. We show the enhancement of some groups of harmonics along the plateau range and the tuning of maximally enhanced harmonic by variable modulation of the plasma. V C 2015 AIP Publishing LLC. [http://dx.

Significant oscillations of the spectral distribution of the idler pulses in the optical parametric amplification of chirped laser pulse have been observed experimentally. On the base of the obtained simple analytical solution we have showed that such oscillations and an asymmetry of the spectral and temporal distributions of the intensities of the signal and the idler were caused by small variations in the parameters of the initial idler in comparison with the signal one. Conditions for distortion of the shape of the temporal and spectral distributions of the amplified compressed output pulses in a multi-stage laser with optical parametric chirped pulse amplification have been determined.

Исследованы нелинейно-оптические характеристики Cr4+:YAG кристалла методикой Zсканирования по схеме с открытой апертурой. В качестве пробного источника использовано излучение непрерывного лазера на длине волны 1030 нм мощностью до 400 мВт. При этом наблюдалось нелинейное поглощение лазерного излучения, которое связано снасыщением возбужденного состояния кристалла. Определена интенсивность насыщения и проведена оценка сечений поглощения в основном и возбужденном состоянияхCr4+:YAG кристалла.

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