High Power Laser Science and Engineering
Colin Danson, Jianqiang Zhu
Volume: 5 Issue 2
8 Article(s)
High Intensity Laser and Attosecond
Liangliang Ji, Sheng Jiang, Alexander Pukhov, Richard Freeman, and Kramer Akli

The improved laser-to-pedestal contrast ratio enabled by current high-power laser pulse cleaning techniques allows the fine features of the target survive before the main laser pulse arrives. We propose to introduce the nano-fabrication technologies into laser–plasma interaction to explore the novel effects of micro-structures. We found out that not only laser-driven particle sources but also the laser pulse itself can be manipulated by specifically designed micro-cylinder and -tube targets, respectively. The proposal was supported by full-3D particle-in-cell simulations and successful proof-of-principle experiments for the first time. We believe this would open a way to manipulate relativistic laser–plasma interaction at the micro-size level.

High Power Laser Science and Engineering
Jun. 29, 2017
  • Vol. 5 Issue 2 02000e14 (2017)
    Target Fabrication
    Bingchi Luo, Jiqiang Zhang, Yudan He, Long Chen, Jiangshan Luo, Kai Li, and Weidong Wu

    The Be-based materials with many particular properties lead to an important research subject. The investigation progresses in the fabrication technologies are introduced here, including main three kinds of Be-based materials, such as Be–Cu capsule, $\text{Be}_{2}\text{C}$ ablator and high-purity Be material. Compared with the pioneer workgroup on Be-based materials, the differences in Be–Cu target fabrication were described, and a grain refinement technique by an active hydrogen reaction for Be coating was proposed uniquely. $\text{Be}_{2}\text{C}$ coatings were first prepared by the DC reactive magnetron sputtering with a high deposition rate $({\sim}300~\text{nm}/\text{h})$. Pure polycrystalline $\text{Be}_{2}\text{C}$ films with uniform microstructures, smooth surface, high density $({\sim}2.2~\text{g}\cdot \text{cm}^{3})$ and good optical transparency were fabricated. In addition, the high-purity Be materials with metal impurities in a ppm magnitude were fabricated by the pyrolysis of organometallic Be.

    High Power Laser Science and Engineering
    May. 05, 2017
  • Vol. 5 Issue 2 02000e10 (2017)
  • Target Fabrication
    I.V. Aleksandrova, and E.R. Koresheva

    In inertial fusion energy (IFE) research, a considerable attention has recently been focused on the issue of large target fabrication for MJ-class laser facilities. The ignition and high-gain target designs require a condensed uniform layer of hydrogen fuel on the inside of a spherical shell. In this report, we discuss the current status and further trends in the area of developing the layering techniques intended to produce ignition, and layering techniques proposed to high repetition rate and mass production of IFE targets.

    High Power Laser Science and Engineering
    May. 31, 2017
  • Vol. 5 Issue 2 02000e11 (2017)
  • Target Fabrication
    Ying Gao, Jianhui Bin, Daniel Haffa, Christian Kreuzer, Jens Hartmann, Martin Speicher, Florian H. Lindner, Tobias M. Ostermayr, Peter Hilz, Thomas F. Rösch, Sebastian Lehrack, Franz Englbrecht, Sebastian Seuferling, Max Gilljohann, Hao Ding, Wenjun Ma, Katia Parodi, and Jörg Schreiber

    We report on a target system supporting automated positioning of nano-targets with a precision resolution of $4~\unicode[STIX]{x03BC}\text{m}$ in three dimensions. It relies on a confocal distance sensor and a microscope. The system has been commissioned to position nanometer targets with 1 Hz repetition rate. Integrating our prototype into the table-top ATLAS 300 TW-laser system at the Laboratory for Extreme Photonics in Garching, we demonstrate the operation of a 0.5 Hz laser-driven proton source with a shot-to-shot variation of the maximum energy about 27% for a level of confidence of 0.95. The reason of laser shooting experiments operated at 0.5 Hz rather than 1 Hz is because the synchronization between the nano-foil target positioning system and the laser trigger needs to improve.

    High Power Laser Science and Engineering
    Jun. 19, 2017
  • Vol. 5 Issue 2 02000e12 (2017)
  • Target Fabrication
    Tina Ebert, Nico W. Neumann, Torsten Abel, Gabriel Schaumann, and Markus Roth

    Ultrashort laser pulses are used to create surface structures on thin ($25~\unicode[STIX]{x03BC}\text{m}$) silicon (Si) wafers. Scanning the wafer with a galvanometric mirror system creates large homogeneously structured areas. The variety of structure shapes that can be generated with this method is exemplified by the analysis of shape, height and distance of structures created in the ambient media air and isopropanol. A study of the correlation between structure height and remaining wafer thickness is presented. The comparatively easy manufacturing technique and the structure variety that allows for custom-tailored targets show great potential for high repetition rate ion acceleration experiments.

    High Power Laser Science and Engineering
    Jun. 19, 2017
  • Vol. 5 Issue 2 02000e13 (2017)
  • Target Fabrication
    Kensuke Tono

    This paper provides a review on sample injectors which are provided at SPring-8 Angstrom Compact free electron LAser (SACLA) for conducting serial measurement in a ‘diffract-before-destroy’ scheme using an x-ray free electron laser (XFEL). Versatile experimental platforms at SACLA are able to accept various types of injectors, among which liquid-jet, droplet and viscous carrier injectors are frequently utilized. These injectors produce different forms of fluid targets such as a liquid filament with a diameter in the order of micrometer, micro-droplet synchronized to XFEL pulses, and slowly flowing column of highly viscous fluid with a rate below $1~\unicode[STIX]{x03BC}\text{L}~\text{min}^{-1}$. Characteristics and applications of the injectors are described.

    High Power Laser Science and Engineering
    Apr. 07, 2017
  • Vol. 5 Issue 2 020000e7 (2017)
  • Target Fabrication
    Sebastian Seuferling, Matthias Alexander Otto Haug, Peter Hilz, Daniel Haffa, Christian Kreuzer, and Jörg Schreiber

    Modern chirped pulse amplification laser systems with continuously improving controllability and increasing power are about to reach intensities of up to $10^{22}~\text{W}~\text{cm}^{-2}$ and have proven their potential to accelerate ions out of plasma to several tens percent of the speed of light. For enabling application, one important step is to increase the repetition rate at which ion bunches are at the disposal. In particular, techniques used so far for thin foil target production can require several days of preparing reasonable amounts for a single campaign. In this paper we describe the reasonably droplet method which we have tested and improved so that the emerging foils with thicknesses of a few nanometres up to micrometre can be used as targets for laser ion acceleration. Their quality and performance can compete with so far employed techniques thereby enabling the production of hundreds of targets per day.

    High Power Laser Science and Engineering
    Apr. 03, 2017
  • Vol. 5 Issue 2 020000e8 (2017)
  • Target Fabrication
    Wenrong Wu, Lie Bi, Kai Du, Juan Zhang, Honggang Yang, and Honglian Wang

    The designs of inertial confinement fusion (ICF) targets, which field on ShenGuang III, are becoming more complex and more stringent in terms of assembly precision. A key specification of these targets is the spatial angle alignment accuracy. To meet these needs, we present a new spatial angle assembly method, using target part’s 3D model-based dual orthogonal camera vision, which is better suited for the flexible automation of target assembly processes. The two-hands structure micromanipulate system and dual orthogonal structure visual feedback system were investigated by considering the kinematics, spatial angle measuring, and motion control in an integrated way. In this paper, we discuss the measurement accuracy of spatial angle assembly method, which compared the real-time image acquisition with the redrawing 2D projection. The result shows that the assembly method proposed is very effective and meets the requirements of angle assembly accuracy, which is less than $1^{\circ }$. Also, this work is expected to contribute greatly to the advancement of other target microassembly equipments.

    High Power Laser Science and Engineering
    May. 03, 2017
  • Vol. 5 Issue 2 020000e9 (2017)
  • Please enter the answer below before you can view the full text.