[en] We consider the generation of beams of highly ionised atoms in solid targets irradiated with CO₂-laser pulses. We present experimental results on generation of Mg and Pb ions from laser plasma at a radiation flux density q ≈ 10¹⁴ W cm^-2. We have developed a theoretical model describing the plasma heating by CO₂-laser radiation at a high pulse intensity on the target, taking into account the ponderomotive forces affecting the behaviour of the interaction of light with the plasma. It is shown that in the case of resonance absorption of laser radiation by the plasma, the efficiency of generation of highly ionised atoms of the target substance is higher than the efficiency of generation in the case of classical absorption. The results of the numerical calculation by the developed model are in good agreement with the experiment.

[en] The paper presents the analysis of interaction of the high-power laser pulse with multicomponent polycrystal rocks. Experiments were completed on a laser facility “Saturn” with intensity of 10¹⁰-10¹³ W/cm². Structural analysis of the materials from the spall crater and from the plasma flame show significant differences. The article demonstrates experimental results of the spall formation moment depending on the thickness of the radiated target. The scale of damage to aluminium 6 pm thick foil at the rare side of the target is illustrated when it is hit by the andesite fragments from a spall crater. (paper)

[en] A CO₂ laser system with self-modulation of the intracavity losses was developed. This system was capable of generating efficiently pulses free of a radiation 'tail' typical for CO₂ lasers. A simple method was used to detect the optical inhomogeneity of the medium of a gas-discharge TEA module. The results of the measurements are presented. (lasers)

[en] CO₂-laser-produced plasma ion component parameters were studied for aluminium and lead targets at laser intensity of P = 4x10¹³ W cm^-2 and pulse duration of τ = 15 ns experimentally and numerically. Angular dependences of ion number density for different charge states, average velocity and its spread were measured by time-of-flight method. Ion charge state distribution shows high-charge and low-charge state groups at normal expansion direction. Ions in these groups have different average expansion velocity and longitudinal velocity spread. Angular distribution of high-charge states is narrower than that of the low-charge state ion group, maximum yield of low-charge states occur at some angle from normal. For Al target results show similar trends as for Pb target, but simulations have indicated that the effect of laser ponderomotive force is more pronounced in this case

[en] In the system consisting of a master oscillator, a three-pass telescopic amplifier, and saturable absorbing cells, CO₂ laser pulses with an energy of 100 J and duration variable from 15 to 80 ns were obtained. A theoretical model for the calculation of interaction of CO₂ laser radiation with resonance absorbing and amplifying media was developed. The system consisting of an absorber saturated at the leading edge of the pulse and an amplifier working in the deep-saturation mode was shown to provide a considerable increase in the gain and pulse compression. (lasers)

[en] Laser interaction with metal and multicomponent polycrystal targets has been studied for laser intensities ranging from 10¹¹ to 10¹² W cm⁻². The temperature inside the plasma, generated near the target surface, was measured with an x-ray filter method. The data obtained for aluminum and andesite targets agree within experimental error with the results calculated on the basis of Mora’s model of plasma expansion. (paper)

[en] Results are presented from experimental and theoretical studies of the efficiency of using a CO₂ laser to create a high-power source of 13- to 14-nm EUV radiation for lithography. For a laser intensity of ∼2 x 10¹¹ W/cm², a conversion efficiency of k_EUV ≅ 1.5% was achieved on a plane solid Sn target. The calculated gas dynamics and population kinetics of Sn plasma ions agree qualitatively with experimental results.