Three gas lenses appear promising for fusion and other applications. We review progress of the understanding and scaling of two of these lenses and discuss their potential for industry, advanced research, and fusion.

A linearly polarized laser pulse has been employed as a wiggler in a free-electron laser (FEL) in the presence of a plasma background for generating short wavelength radiation down to the extreme ultraviolet ray and X-ray spectral regions. Introducing plasma background in the FEL interaction region would lessen the beam energy requirement and also enhance both the beam current and the electron-bunching process. This configuration affords the possibility of scaling the device to more compact FELs and would have a higher tunability by changing the plasma density and the temperature of the electron beam. Electron trajectories have been analyzed using single-particle dynamics. The effect of plasma density on electron orbits has been investigated. A polynomial dispersion relation considering longitudinal thermal motion has been derived, by employing perturbation analysis. Numerical studies indicate that by increasing plasma density, the growth rate for groups I and II decreases, while the growth rate for group III increases. In addition, the effect of beam temperature and cyclotron frequency on the growth rate has been discussed. It has been found that by increasing the thermal velocity of the electron beam, the growth rate for groups I and III trivially decreases, while it increases for group II orbits. Besides, an increase in cyclotron frequency cause growth enhancement for group I orbits, while it present a growth decrement for group II and III orbits.

X-ray emission from planar targets irradiated by 1.054-μm laser pulses was observed with temporal, spatial, and spectral resolution. The main purpose of these measurements was the investigation of energy transfer in multilayer targets and X-ray conversion efficiency. A mass ablation rate was determined from temporal analysis of multicharged ion line emission and a key role of corona X-ray emission in accelerated material preheating was established.

The dependence of the high-order harmonic cutoff spectrum from the absolute phase of the laser pulse is here experimentally investigated. Noticeable shifts are observed. Their interpretation is proposed with a model based on the absolute-phase dependence of the trajectories of the photoelectrons that contribute to a given harmonic order.

The laser-induced breakdown spectroscopy (LIBS) technique is one of the most promising laser-based analytical techniques. Coincidentally, the LIBS acronym was proposed by Radziemski and Loree in two seminal papers published in 1981, almost at the same time in which the Laser and Particle Beams journal started its publication. In this contribution, the evolution of the LIBS technique is discussed following a chronological collection of key papers in LIBS, some of which were in fact published on LPB.