The possibility of observing the stimulated de-excitation of nuclear isomers (SDENI) in plasma (plasma lifetime ∼1.5 ps, temperature of electrons ∼ 10 keV) formed by the impact of a high-power laser pulse (∼10 18 W cm −2 ) on a target is studied experimentally. Preliminary experiments are carried out with the 110 m Ag ( T 1/2 = 250 days) and 186 m Re ( T 1/2 = 2 × 10 5 years) isomers. A weak SDENI effect is observed only for the 110 m Ag isomer on a platinum backing.

This paper presents the optical layout and composition of a system for automatically adjusting the multipass power module of a next-generation laser apparatus. An adjustment technique based on near-field and far-field markers is described. A control program under the Astra Linux operating system is described for the automatic-adjustment system.

This paper presents the results of studies of the acceleration of macroparticles consisting of fragments of matter from the back side of a solid target when its front surface is irradiated with a picosecond laser pulse with intensity 10(13) - 10(15) W/cm(2). It is experimentally shown that there are optimal conditions for maximizing the spalling momentum of the target fragments, depending on its thickness and the intensity of the laser pulse on the front surface. The focusing of melted fragments of the substance, split off from the back surface of a target made in the form of a hemisphere, is experimentally demonstrated. The spalling momentum from such a target is greater than the momentum from a flat target of the same thickness by a factor of 6-7. (C) 2009 Optical Society of America.

It was found that maximum particle output and best possible spatial uniformity of proton beam took place for two-layer target when the front layer was the high-Z film. It was shown that the ion radiography of the convenient objects with using the two-layer targets allow to get the projecting pictures with high spatial resolution that was about one micron. Threshold spatial sensitivity of proton radiography is estimated.

Laser plasma produced with high-intensity picosecond laser pulse like proton source for radiography was investigated. It was found that maximum particle output and best possible spatial uniformity of proton beam took place for two-layer target when the front layer was the high-Z film. It was shown that the ion radiography of the convenient objects with using the two-layer targets allow to get the projecting pictues with high spatial resolution that was about one micron. The explanation of such high spatial resolution is in laminar motion of ion flow. Threshold spatial sensitivity of proton radiography is estimated.

A mirror-lens objective has been developed that focuses a powerful laser beam with a planar wavefront into a straight line 10 mm long. The objective is intended for the creation of extended plasma objects. The construction involves an improved version of Maksutov's meniscus system, based on a toroidal mirror. A sample with an effective diameter of 130 mm and a relative aperture of 1:2.4 has been fabricated and investigated.

This paper discusses features of the fabrication of focusing objectives based on an off-axis parabolic mirror with large asphericity (more than 350 mum) and a large asphericity gradient (about 20 mum/mm). The objectives are intended to concentrate the radiation of a picosecond laser. The effective diameter of the objectives is 145 mm, and the relative aperture is 1: 1.4. The aspheric surface is fabricated by automatically processing the optical surfaces with a small tool on an AD-1000 machine. Up to 83% of the energy of a plane wave at the fundamental frequency of a neodymium laser is concentrated at a focal point 9 mum in diameter. (C) 2002 Optical Society of America.

The results of work on creation of a system for remote control alignment of high-power multichannel Nd-glass laser systems, being created in VNIIEF and NIIEFA, are presented. Methods and principles of alignment, high-accuracy driving units for mirrors tilts and pinholes travels, CCD-sensor capable of accepting weak radiation fluxes with a wavelength lambda =1,053 mum are considered.

The interaction of a 1053 nm picosecond laser pulse with a solid target for focused intensities of up to 10(19) W/cm(2) are studied by measurements of the absorption of the laser light in the plasma and by measurements of the production of hard X-rays. Absorption measurements are made by collecting the scattered light in set of calorimeters. Light scattered in backward and specular directions is collected separately. Measurements are presented for both high and low Z targets. Hard X-ray spectrum in range 15 - 1000 keV and hot electron production in range 1 - 22 MeV are measured using a multichannel filter/scintillator and filter/semiconductor spectrometers. Spatial parameters of fast ions are studied.

Results are presented from an investigation of the hard X-ray spectrum and the parameters of fast particles in experiments on the interaction of laser pulses with solid targets in the PROGRESS-P facility at laser intensities of up to 5×10 18 W/cm 2 on the target surface. The maximum energy of fast electrons obtained from direct measurements is found to be 8–10 MeV.

We present the key features of design and performance of PROGRESS-P CPA Nd:YLF/Nd:glass laser facility capable of producing 1.5-ps pulses and a power up to 30 TW at the wavelength 1053 nm for laser-plasma experiments in ultrahigh irradiance on the target up to 10(19) W/cm(2). We describe voltage pulse drivers based on drift step recovery diodes which produce output voltage up to 15 kV, rise time similar to 1ns, jitter of 100 ps and repetition rate up to 10 kHz to electrooptical devices.

The scattering and absorption of a high-power picosecond laser pulse by a solid target were investigated experimentally making use of the 'Progress-P' Nd:glass laser facility (λ = 1053 nm, τ = 1.4 ps) at radiation intensities I = 1016 — 1019 W cm-2 on the target surface. It was found that, for I ≤ 1017 W cm-2, more than 30% of the intensity of the scattered light was contained in the specularly reflected component. The absorption coefficient of the laser radiation with intensities ranging from 1018 to 1019 W cm-2 was higher for targets made of materials with higher atomic numbers.

A Nd:YLF/Nd:glass laser facility with chirped-pulse amplification capable of generating pulses with a duration of 1.5 ps and a power up to 30 TW at the wavelength of 1053 nm was investigated. The facility consists of a initial laser system, producing a chirped pulse with an energy up to ~1 J, a main three-stage rod amplifying channel with a 85-mm aperture of the output stage, a pulse compressor based on 210 mm × 420 mm diffraction gratings, and a focusing axial parabolic mirror (with an aperture ratio of 1:11). Optimisation of the parameters of the laser facility allowed us to generate an output laser beam with an angular divergence close to the diffraction limit and an intensity up to ~1019 W cm-2 . Laser radiation with such parameters can be employed in experiments on the interaction of superstrong laser fields with matter.

We present the parameters of compressor and focusing systems of 30-TW Nd:glass laser facility "Progress-P" and results of experimental investigation of beam propagation through this systems. Near diffraction-limited beam quality is obtained at output laser amplifier chain by use the low-thermal phosphate Nd:glass and high quality optical elements. Output 180 mm beam is compressed using two holographic gratings with dimensions 420x210 mm and focused on targets by means on-axis parabolic mirror with focal length of 200 mm. About 50% energy is obtained in 8 mu m focal spot in target chamber for low power beam. Investigations of the focal spot characteristics for high-power beam are under way.

On the PROGRESS laser facility the spectral and spatial characteristics of suprathermal particles extension in experiments with flat targets and picosecond duration of heating laser pulse are investigated. The opportunity to use multiframe pulse interferometry for visualization of spatial and power parameters of suprathermal particle extension alongside with traditional means of charged particle diagnostics with an irradiation of flat targets in an atmosphere of residual gas are considered. The basic part of laser radiation with energy up to 20 J and pulse duration 200 ps is directed to target chamber. A few parts of a heated laser pulse amplified and compressed with Raman backscattering compressor up to 10-20 ps with energy 20-30 mJ and wavelength 622 nm was used as optical diagnostic beam in multiframe interferometer. Series of experiments both with p and with the s-polarized radiation were carried out. On the basis of received interferograms the measurements of spectral parameters of fast particles by traditional methods with time-of-flight technique are carried out. This data are compared with spatial distribution of fast ions at picosecond laser-plasma experiments and laser intensity up to 1019 W/cm2 on the PROGRESS-P laser.