No abstract available

No abstract available

[en] Mirror-lense objectives achromatized for effective (λ₁=1.315 μm) and positioning (λ₂=0.63 μm) wavelengths of 700 mm in diameter with focus distance of 1100 mm are developed and produced. Lense aspherical objectives are developed to irradiate targets by the second harmonics radiation (0.66 μm)

[en] Using molecular dynamics simulation we study the response of a spherical nanoparticle (NP) to a sudden homogeneous energization, such as effected by ultrashort pulse laser irradiation. We consider a Lennard-Jones model system and two different values of the energization. For the smaller one, the sphere expands while a multitude of voids are created inside; the sphere develops finally into an external shell filled with gas and small clusters. For the higher energization, the sphere expands uniformly and no shell structure is formed. An analysis of the pressure generated confirms that in the latter case the pressure is compressive throughout the sphere expansion, while it is temporarily tensile for the lower energization leading to void formation. The final state of both systems shows the fragmentation of the sphere into a multitude of clusters. With increasing fragmentation the cluster distribution becomes shifted to smaller sizes. Simulated small-angle scattering functions of the exploding NP are presented. The distribution of minima allows for an easy determination of the particle size during expansion. (authors)

[en] The permissible background energy is analyzed taking into account matching between the main heating pulse and the target in order to derive expressions for the required level of the energy contrast. It is shown that the required contrast value can amount to approximately 10⁶ under conditions of the compressing shell

[en] An efficient way for manipulating ultraintense laser pulses in plasmas using resonant three-wave interactions is proposed. Poor quality ultraintense laser pulses can be efficiently transformed into high quality focused laser pulses, while the entropy is taken up by resonant plasma waves. This can be accomplished within plasma layers thin enough that parasitic scatterings and instabilities of laser pulses do not have enough time to develop. Combined with laser pulse compression in plasmas, this scheme, using, for example, the lasers that power the National Ignition Facility (see, for instance, the NIF project website: http://www.llnl.gov/nif/project), is potentially capable of producing vacuum breakdown intensities

[en] The analysis of thermal processes during the measurement of coating thickness with the use of heating with laser radiation is conducted. The obtained curves of the heating process allow determining thickness of the formed coatings. (paper)

[en] This paper reports an experimental study on preheating of laser-irradiated targets. We performed temperature measurements at the rear surface of laser-irradiated targets under conditions of two different laser wavelengths (0.35 or 0.53 μm) and several intensities (2x10¹³-1x10¹⁴ W/cm²) in order to verify an effect of radiation and nonlocal electron heat transport. The preheating temperature was evaluated by observing self-emission, reflectivity, and expansion velocity at the rear surface of planar polyimide foils. The experimental results show that the x-ray radiation is dominant for preheating for 0.35-μm laser irradiation, but contribution of nonlocal electron heat transport is not negligible for 0.53-μm laser irradiation conditions.

[en] By now laser conditioning has been proved to be an useful method to improve the optical coatings and raise the laser induced damage threshold (LIDT) of the thin film coatings. However, whatever happens during the laser conditioning process and whichever factor influences the laser conditioning effect are still not very clear. We Produce a series samples with different roughness levels of the substrates, multilayer design, thin film material and the vacuum environment of the chamber. We make laser conditioning test to these samples by 1.06 μm laser. Photothermal deflection technology (PDT) is employed to observe the conditioning process in-situ. A series of experimental data are obtained. We give our explanation. The mechanism of laser conditioning, is also discussed

[en] The results of diamond synthesis investigation are represented. Using CO-2 laser beam, by means of substance radiation containing carbon micro-crystals of diamond are obtained. The fact of diamond synthesis by X-ray structure analysis of substance radiation is confirmed. 7 refs