We present results from a pitcher-catcher experiment utilizing a proton beam generated with nanostructured targets at a petawatt-class, short-pulse laser facility to induce proton-boron fusion reactions in a secondary target. A 45-fs laser pulse with either 400 nm wavelength and 7 J energy, or 800 nm and 14 J, and an intensity of up to 5 × 1021 W/cm2 was used to irradiate either thin foil targets or near-solid density, nanostructured targets made of boron nitride (BN) nanotubes. In particular, for 800 nm wavelength irradiation, a BN nanotube target created a proton beam with about five times higher maximum energy and about ten times more protons than a foil target. This proton beam was used to irradiate a thick plate made of boron nitride placed in close proximity to trigger 11B (p, α) 2α fusion reactions. A suite of diagnostics consisting of Thomson parabola ion spectrometers, postshot nuclear activation measurements, neutron time-of-flight detectors, and differentially filtered solid-state nuclear track detectors were used to measure both the primary proton spectrum and the fusion products. From the primary proton spectrum, we calculated (p, n) and (α,n) reactions in the catcher and compare with our measurements. The nuclear activation results agree quantitatively and neutron signals agree qualitatively with the calculations, giving confidence that primary particle distributions can be obtained from such measurements. These results provide new insights for measuring the ion distributions inside of proton-boron fusion targets.

In the 2015 review paper ‘Petawatt Class Lasers Worldwide’ a comprehensive overview of the current status of high-power facilities of ${>}200~\text{TW}$ was presented. This was largely based on facility specifications, with some description of their uses, for instance in fundamental ultra-high-intensity interactions, secondary source generation, and inertial confinement fusion (ICF). With the 2018 Nobel Prize in Physics being awarded to Professors Donna Strickland and Gerard Mourou for the development of the technique of chirped pulse amplification (CPA), which made these lasers possible, we celebrate by providing a comprehensive update of the current status of ultra-high-power lasers and demonstrate how the technology has developed. We are now in the era of multi-petawatt facilities coming online, with 100 PW lasers being proposed and even under construction. In addition to this there is a pull towards development of industrial and multi-disciplinary applications, which demands much higher repetition rates, delivering high-average powers with higher efficiencies and the use of alternative wavelengths: mid-IR facilities. So apart from a comprehensive update of the current global status, we want to look at what technologies are to be deployed to get to these new regimes, and some of the critical issues facing their development.

Recent results in the development of diode-driven high energy, high repetition rate, picosecond lasers, including the demonstration of a cryogenic Yb:YAG active mirror amplifier that produces 1.5 J pulses at 500 Hz repetition rate (0.75 kW average power) are reviewed. These pulses are compressed resulting in the generation of ${\sim}5~\text{ps}$ duration, 1 J pulses with 0.5 kW average power. A full characterization of this high power cryogenic amplifier, including at-wavelength interferometry of the active region under ${>}1~\text{kW}$ average power pump conditions, is presented. An initial demonstration of operation at 1 kW average power (1 J, 1 kHz) is reported.

A preliminary investigation on short-wavelength ablation mechanisms of poly(methyl methacrylate) (PMMA) and poly (1,4-phenylene ether ether-sulfone) (PPEES) by extreme ultraviolet (EUV) radiation at 13.5 nm using a table-top laser-produced plasma from a gas-puff target at LLG (Göttingen) and at 46.9 nm by a 10 Hz desktop capillary discharge laser operated at the Institute of Physics (Prague) is presented. Ablation of polymer materials is initiated by photo-induced polymer chain scissions. The ablation occurs due to the formation of volatile products by the EUV radiolysis removed as an ablation plume from the irradiated material into the vacuum. In general, cross-linking of polymer molecules can compete with the chain decomposition. Both processes may influence the efficiency and quality of micro(nano)structuring in polymer materials. Wavelength is a critical parameter to be taken into account when an EUV ablation process occurs, because different wavelengths result in different energy densities in the near-surface region of the polymer exposed to nanosecond pulses of intense EUV radiation.

We have developed a compact, 14.7 nm, sub-5 ps X-ray laser source at Lawrence Livermore National Laboratory (LLNL) together with a Mach-Zehnder type diffraction grating interferometer built at Colorado State University for probing dense, high intensity laser-produced plasmas. The short wavelength and pulse length of the probe reduces refraction, absorption effects within the plasma and minimizes plasma motion blurring. This unique diagnostic capability gives precise two-dimensional (2D) density profile snapshots and is generating new data for rapidly evolving laser-heated plasmas. A review of the results from dense, mm-scale line focus plasma experiments will be described with detailed comparisons to hydrodynamic simulations.

Polycrystalline diamond films were processed in a direct current plasma produced by a self-focused electron beam using combinations of H2, O2, and He as the processing gas. The film surfaces were observed by scanning electron microscopy, and characterized by x-ray photoelectron spectroscopy. It was found that for the case in which O2 was included in the processing gas, a high density of etch pits appeared on (100) faces of diamond grains, and oxygen was either physisorbed or chemisorbed at the film surface. It was demonstrated that the etching apparatus used was capable of forming at least a 5-μm wide pattern of polycrystalline diamond film.

A large area (2.8 cm2) electron beam source has been developed, characterized, and applied to anisotropic etching of SiO2 masked with photoresist. This beam operates at high pressures (up to 100 mTorr), in reactive gases, and at more than 10 mA/cm2. Beam current can be controlled in several ways independently from beam energy. The 100 – 900 eV low energy beam propagates with collimation through several cm of reactive gas, and is believed to minimize space charge defocusing by collisionally ionizing the working gas.