Fabrication of disk-shaped, deuterated resorcinol/formaldehyde foam target for laser–plasma experiments

Resorcinol/formaldehyde (RF) foam resin is an attractive material as a low-density target in high-power laser–plasma experiments because of its fine network structure, transparency in the visible region, and low-Z element (hydrogen, carbon, and oxygen) composition. In this study, we developed disk-shaped RF foam and deuterated RF foam targets with 40–200 µm thickness and approximately 100 mg/cm3 density having a network structure from 100 nm to a few micrometers cell size. By deuteration, the polymerization rate was drastically slowed down owing to kinetic isotope effects. These targets were used in high-power laser experiments where a megaelectronvolt proton beam was successfully generated.Kaneyasu Y., Nagai K., Cadatal-Raduban M., et al. Fabrication of disk-shaped, deuterated resorcinol/formaldehyde foam target for laser–plasma experiments. High Power Laser Science and Engineering 9, e31 (2022); https://doi.org/10.1017/hpl.2021.15

Split-aperture laser pulse compressor design tolerant to alignment and line-density differences

This paper was published in Optics Letters and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://dx.doi.org/10.1364/OL.33.001902 Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law

Pulse compression and beam focusing with segmented diffraction gratings in a high-power chirped-pulse amplification glass laser system

This paper was published in Optics Letters and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://dx.doi.org/10.1364/OL.35.001783 Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law

Cryogenic deuterium target experiments with the GEKKO XII, green laser system

Copyright 1995 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Physics of Plasmas, 2(6), 2495-2503, 1995 and may be found at http://dx.doi.org/10.1063/1.87121

Simple and Downsized Amplification System of a Femtosecond Laser Pulse using Dye Gain Media

A femtosecond laser pulse of a fiber laser is amplified in dye gain media. To evaluate the conditions for the amplification of a femtosecond laser pulse, the time-resolved measurements of gains in OXAZINE 750, DOTC, and LDS 821 dye solutions are carried out by using a TEA N2 laser (λ= 337.1 nm, FWHM= 0.6 ns), a TE N2 laser (λ= 337.1 nm, FWHM= 6 ns) and the second harmonic of a Nd:YAG laser (λ= 532 nm, FWHM= 5 ns), as the pump sources. The amplified output energy of the fs laser pulse is 1 μJ, and the pulse width is 180 fs (FWHM). These output energy and pulse width are comparable to those of a typical CPA laser system, and the cost performance is very high

Hot electron and ion spectra on blow-off plasma free target in GXII-LFEX direct fast ignition experiment

Polystyrene deuteride shell targets with two holes were imploded by the Gekko XII laser and additionally heated by the LFEX laser in a direct fast ignition experiment. In general, when an ultra-intense laser is injected into a blow-off plasma created by the imploding laser, electrons are generated far from the target core and the energies of electrons increase because the electron acceleration distance has been extended. The blow-off plasma moves not only to the vertical direction but to the lateral direction against the target surface. In a shell target with holes, a lower effective electron temperature can be realized by reducing the inflow of the implosion plasma onto the LFEX path, and high coupling efficiency can be expected. The energies of hot electrons and ions absorbed into the target core were calculated from the energy spectra using three electron energy spectrometers and a neutron time-of-flight measurement system, Mandala. The ions have a large contribution of 74% (electron heating of 4.9 J and ion heating of 14.1 J) to target heating in direct fast ignition