Ag thin films were deposited by pulsed laser ablation in a controlled Ar atmosphere. The deposition process was performed at different Ar pressure values in the range between 10 and 100 Pa to investigate the influence of ambient gas pressure on the plasma expansion dynamics and on the film structural properties. Position, velocity and volume of the laser generated plasma as functions of time were obtained by time resolved fast photography. The morphological properties of the films were investigated by transmission electron microscopy which shows that film growth proceeds via aggregation on the substrates of nanoclusters formed in the expanding plume. The formation of nanoparticles takes place as a consequence of plasma confinement induced by the interaction with ambient gas species. Data from fast photography analysis were used as input parameters to calculate the size of the nanoparticles using a model that takes into account the collisional nature of the laser generated silver plasma.

Energy enhancement by a circularly polarized laser pulse during acceleration of the electrons by a Gaussian laser pulse has been investigated. The electrons close to the temporal peak of the laser pulse show strong initial phase dependence for a linearly polarized laser pulse. The energy gained by the electrons close to the rising edge of the pulse does not show initial phase dependence for either linearly- or circularly-polarized laser pulse. The maximum energy of the electrons gets enhanced for a circularly polarized in comparison to a linearly polarized laser pulse due to axial symmetry of the circularly polarized pulse. The variation of electron energy with laser spot size, laser intensity, initial electron energy, and initial phase has been studied.

The presence of an axial magnetic field in a laser beat wave accelerator enhances the oscillatory velocity of electrons due to cyclotron resonance effect leading to higher amplitude of the ponderomotive force driven plasma wave, and higher energy of accelerating electrons. The axial magnetic field inhibits the transverse escape of electrons and thus causes a growth of the interaction length. The surfatron acceleration of electrons also shows a similar enhancement. A surfatron transverse magnetic field deflects the electrons parallel to the phase fronts of the accelerating wave keeping them in phase with it. However, the electron continues to move away radially.

An overview of the equations of state (EOS) with a short summary of shock wave experiments with laser induced impact flyer, relevant to EOS study, is presented. The “old-new” ellipsometry is suggested and described for the EOS research. The detection of phase transitions of the first kind (solid-solid) as well as phase transition of the second kind (Curie point as an example) is demonstrated. Furthermore, the temperature measurements are not possible without the knowledge of the emissivity, a parameter that can be measured by using ellipsometry techniques.

We will theoretically and experimentally study the effect of the linewidth and the frequency of a weak detuned signal on its amplified spectrum in the Brillouin amplifier. We will show that the spectral profile of the input signal is preserved during amplification only when the signal linewidth is much narrower than the Brillouin linewidth of the amplifier. If the signal linewidth is near or above the Brillouin linewidth, the frequency shift of the amplified signal with respect to the pump will be close to the Brillouin shift of the amplifier, and will be independent of the frequency shift of the input signal.

Surface plasmon enhanced electron acceleration is a recently discovered efficient particle acceleration phenomenon in the nanoscale-confined field of surface electromagnetic waves. For the generation and spatial/spectral control of keV-energy electrons generated, this way few-cycle laser pulses can be utilized particularly well. We present numerical results based on a simple model of this phenomenon analogous to the three-step model of high harmonic generation. We identify those parameter regimes where the emitted electron beam is highly directional and monoenergetic opening the door to novel ultrafast applications and methods.

Interaction of a Nd:YAG laser, operating at wavelengths of 1064 nm (23.6 J cm−2 fluence) or 532 nm (25.9 J cm−2 fluence), and pulse duration of 40 ps, with a titanium-based medical implant Ti6Al4V alloy was studied. Surface damage thresholds were estimated to be 0.9 J cm−2 and 0.25 J cm−2 at laser wavelengths 1064 nm and 532 nm, respectively. At both laser wavelengths, the energy absorbed was mostly converted into thermal energy, forming craters, albeit about 50 times deeper at 1064 nm than at 532 nm. Periodic surface structures (PSS) were also formed with both laser wavelengths, concentric, and radial at micrometer scale (3 µm to 15 µm period), parallel at nanometer scale (800 nm period with the 1064 nm laser, 400 nm with the 532 nm laser). In the case of the 532 nm laser, the concentric structures enlarge their period with accumulating laser pulse count. These features can help roughening of the implant surface and improve bio-compatibility.

The development activity of a new experimental technique for the study of the fast electron transport in high density matter is reported. This new diagnostic tool enables the X-ray 2D imaging of ultrahigh intensity laser plasmas with simultaneous spectral resolution in a very large energy range to be obtained. Results from recent experiments are discussed, in which the electron propagation in multilayer targets was studied by using the Kα. In particular, results highlighting the role of anisotropic Bremsstrahlung are reported, for the sake of the explanation of the capabilities of the new diagnostics. A discussion of a test experiment conceived to extend the technique to a single-shot operation is finally given.

A non-collinear laser beam combination based on Brillouin amplification is proposed. The influence of non-collinear Brillouin amplification on the combination efficiency is analyzed and discussed theoretically. It is shown that an efficiency of 80% can be achieved with the angle between the Stokes and the pump limited to a range of 10°. The theoretical prediction is tested in experiment of non-collinear amplification of one Stokes and one pump. A two-beam combination scheme is designed and a high combination efficiency of 80% is also obtained in this experiment. According to these results, a 20-beam combination scheme is designed to achieve 13.2-J output energy. A very simple construction for a multiple beams combination is designed.

In order to measure the phase conjugation-fidelity of stimulated Brillouin scattering with high pump energy more accurately and conveniently, a new measurement is proposed. According to the definition of the fidelity with optical field correlated integral, the method of recording the far-field by array camera is analyzed theoretically. By the method, an experiment for high energy stimulated Brillouin scattering is arranged, and the maximum energy of 3.42 J is achieved in a single-cell stimulated Brillouin scattering generator. For small pump pulse, the fidelity maintains a high value of more than 0.9. However, the reflectivity fluctuation is significant when the pump energy is larger than 1.5 J. As a result, the fidelity decreases gradually to 0.5 at the pump energy of 3.42 J. The reflectivity shows the same character of great fluctuation as the fidelity at high pump energy.

A two-layer target irradiated by an intense laser to generate strong interface magnetic field is proposed. The mechanism is analyzed through a simply physical model and investigated by two-dimensional particle-in-cell simulation. The effect of laser intensity on the resulting magnetic field strength is also studied. It is found that the magnetic field can reach up to several ten megagauss for laser intensity at 1019 Wcm−2.

We present an easy-to-use formula for mean (space- and direction-average) specific intensity of radiation in uniform spherical and cylindrical plasmas, which are not under external irradiation. This formula has high accuracy in any spectral interval dν taken in continuum as well as within a spectral line of any profile, including overlapping lines and lines on a pedestal of intense continuum in any spectral range. The formula considerably accelerates self-consistent computations of the radiation field and the distribution of ions over their ionization degrees and quantum states. It may also be used for computations of any radiation dependent-quantity, for example, the photoionization probability.

The Large Hadron Collider (LHC) will operate with 7 TeV/c protons with a luminosity of 1034 cm−2 s−1. This requires two beams, each with 2808 bunches. The nominal intensity per bunch is 1.15 × 1011 protons and the total energy stored in each beam is 362 MJ. In previous papers, the mechanisms causing equipment damage in case of a failure of the machine protection system was discussed, assuming that the entire beam is deflected onto a copper target. Another failure scenario is the deflection of beam, or part of it, into carbon material. Carbon collimators and beam absorbers are installed in many locations around the LHC close to the beam, since carbon is the material that is most suitable to absorb the beam energy without being damaged. In case of a failure, it is very likely that such absorbers are hit first, for example, when the beam is accidentally deflected. Some type of failures needs to be anticipated, such as accidental firing of injection and extraction kicker magnets leading to a wrong deflection of a few bunches. Protection of LHC equipment relies on the capture of wrongly deflected bunches with beam absorbers that are positioned close to the beam. For maximum robustness, the absorbers jaws are made out of carbon materials. It has been demonstrated experimentally and theoretically that carbon survives the impact of a few bunches expected for such failures. However, beam absorbers are not designed for major failures in the protection system, such as the beam dump kicker deflecting the entire beam by a wrong angle. Since beam absorbers are closest to the beam, it is likely that they are hit first in any case of accidental beam loss. In the present paper we present numerical simulations using carbon as target material in order to estimate the damage caused to carbon absorbers in case of major beam impact.

Unconventional, promising approaches to inertial fusion energy (IFE) proposed and studied in the framework of IFE keep-in-touch activity at Frascati EURATOM-ENEA Association will be reconsidered for the present more advanced technological context associated to a planned large installations scenario. Then the possibility to generate laser-produced fast heavy-ion sources (e.g., Bi ions, tens GeV) will be explored taking as reference results obtained in the FIGEX experiment scaled toward thermonuclear regimes. A possible dimensioning of such sources will be also given as well as the associated laser requirements.

Results in some directions of the target technology for research on high energy density and laser fusion at the Russian Federal Nuclear Centre–All-Russia Research Institute of Experimental Physics for the last three years are presented. The results of development of optical and X-ray methods of characterization and manufacturing techniques of targets for studying the equation-of-state at high pressures and the condensed rare gas targets for the influence of pulse-repeated laser irradiation are given.

The pulse forming line (PFL) is the key part of the intense electron-beam accelerators (IEBA), which determines the quality and characteristic of the output beam current of the IEBA. Compared with the accelerator with traditional Blumlein line, an IEBA based on strip spiral Blumlein line (SSBL) can increase the duration of the output pulse in the same geometrical dimension. But the disadvantage of the SSBL is that the output voltage waveform at the matched load may be distorted, which influences the electron beam quality. In this paper, according to the electromagnetic theory, formulas for calculating the main electric parameters of SSBL (inductance, capacitance, transmission time, and characteristic impedance) are deduced. The effect of the geometric parameters of SSBL on the slowing coefficient is analyzed. The designed condition of SSBL for the output ideal voltage pulse in the matched load is obtained by theoretical analysis. Furthermore, the Karat code is used to simulate the output voltage waveform of SSBL on the matched load for different spiral angels. At last, a couple of contrastive experiments are performed on an electron-beam accelerator based on the SSBL with water dielectric. The experimental results agree with the theoretical and simulated results.

With the advent of intense, coherent light sources in the XUV and soft X-ray regime, X-ray Thomson scattering becomes a unique tool for the diagnostics of dense plasmas. The scattering spectrum gives direct access to plasma properties like density, temperature, and composition. In dense systems, collisions among constituents are of primary importance for the prediction and interpretation of the scattering signal. We present a systematic approach to the dynamical structure factor using the Born-Mermin ansatz to include collisions via the dynamical collision frequency. Calculations of the scattering spectrum are performed for X-ray scattering on solid and compressed beryllium targets as well as for XUV-photons scattering on hydrogen at near solid density.

A novel composite optical phase conjugator that combines Brillouin-enhanced four-wave mixing (BEFWM) and stimulated Brillouin amplification (SBA) in a compact structure is reported. A phase-conjugate wave seed is generated by BEFWM process with characteristics such as fast response, high conjugate fidelity and stability, then it is magnified by SBA with high energy-conversion efficiency. As a result, advantages of BEFWM and SBS can be realized at the same time. This composite conjugator has potentials for high-peak and high-average power laser applications, especially for short pulse or steep leading-edge pulse laser systems. Feasibility of this BEFWM-SBA mechanism is verified in theoretical simulations and demo experiments.

Monoenegetic ion beam generation from circularly polarized laser-pulse interaction with a double-layer target is considered. The front layer consists of heavy-ion plasma, and the rear layer is a small thin coating of light-ion plasma. Particle-in-cell simulation shows that the multi-dimensional effects in the ion radiation pressure acceleration are avoided and a highly monoenergetic light-ion beam can be produced. Our simulations reveal that the charge-mass ratio of heavy ions in the front layer and the thicknesses of both layers can strongly affect the proton energy spectra.

The interaction of an Nd:YAG laser, operating at 532 nm with 40 ps pulse duration, with human teeth was studied. The results show that teeth were significantly modified at an energy fluence of about 11 J/cm2. Various surface morphologies of enamel and dentine were recorded. Features on enamel include crater (conical form) in the central part and cauliflower morphology at the periphery, whereas on dentine the crater looks like a stretched dome between sharp edges. The behavior of the enamel-dentine junction area showed different morphology with respect to both tooth enamel and dentine alone. Finally, the junction channel showed a removal of collagen fibers and the formation of a needle-like bottom structure. Generally, this investigation showed that the picosecond Nd:YAG laser can ablate a tooth surface practically instantaneously, implying that large tooth surfaces can be processed in short time.