High Power Laser Science and Engineering
Co-Editors-in-Chief
Colin Danson, Jianqiang Zhu
2016
Volume: 4 Issue 3
14 Article(s)
Wanguo Zheng, Xiaofeng Wei, Qihua Zhu, Feng Jing, Dongxia Hu, Jingqin Su, Kuixing Zheng, Xiaodong Yuan, Hai Zhou, Wanjun Dai, Wei Zhou, Fang Wang, Dangpeng Xu, Xudong Xie, Bin Feng, Zhitao Peng, Liangfu Guo, Yuanbin Chen, Xiongjun Zhang, Lanqin Liu, Donghui Lin, Zhao Dang, Yong Xiang, and Xuewei Deng

SG-III laser facility is now the largest laser driver for inertial confinement fusion research in China. The whole laser facility can deliver 180 kJ energy and 60 TW power ultraviolet laser onto target, with power balance better than 10%. We review the laser system and introduce the SG-III laser performance here.

Jan. 01, 1900
  • Vol. 4 Issue 3 03000e21 (2016)
  • C. Riconda, and S. Weber

    The co-existence of the Raman and Brillouin backscattering instability is an important issue for inertial confinement fusion. The present paper presents extensive one-dimensional (1D) particle-in-cell (PIC) simulations for a wide range of parameters extending and complementing previous findings. PIC simulations show that the scenario of reflectivity evolution and saturation is very sensitive to the temperatures, intensities, size of plasma and boundary conditions employed. The Langmuir decay instability is observed for rather small kepwD but has no influence on the saturation of Brillouin backscattering, although there is a clear correlation of Langmuir decay instability modes and ion-fractional decay for certain parameter ranges. Raman backscattering appears at any intensity and temperature but is only a transient phenomenon. In several configurations forward as well as backward Raman scattering is observed. For the intensities considered, I2oabove 1015 W mm2=cm2, Raman is always of bursty nature. A particular setup allows the simulation of multi-speckle aspects in which case it is found that Raman is self-limiting due to strong modifications of the distribution function. Kinetic effects are of prime importance for Raman backscattering at high temperatures. No unique scenario for the saturation of Raman scattering or Raman–Brillouin competition does exist. The main effect in the considered parameter range is pump depletion because of large Brillouin backscattering. However, in the low kepwD regime the presence of ion-acoustic waves due to the Langmuir decay instability from the Raman created electron plasma waves can seed the ion-fractional decay and affect the Brillouin saturation.0.0/15-008/0000162) from European Regional Development.

    Jan. 01, 1900
  • Vol. 4 Issue 3 03000e23 (2016)
  • Nasr A.M. Hafz, Song Li, Guangyu Li, Mohammad Mirzaie, Ming Zeng, and Jie Zhang

    Ionization-induced electron injection in laser wakefield accelerators, which was recently proposed to lower the laser intensity threshold for electron trapping into the wake wave, has the drawback of generating electron beams with large and continuous energy spreads, severely limiting their future applications. Complex target designs based on separating the electron trapping and acceleration stages were proposed as the only way for getting small energy-spread electron beams. Here, based on the self-truncated ionization-injection concept which requires the use of unmatched laser–plasma parameters and by using tens of TW laser pulses focused onto a gas jet of helium mixed with low concentrations of nitrogen, we demonstrate single-stage laser wakefield acceleration of multi-hundred MeV electron bunches with energy spreads of a few percent. The experimental results are verified by PIC simulations.

    Jan. 01, 1900
  • Vol. 4 Issue 3 03000e24 (2016)
  • Fei-Lu Wang, Xiao-Xing Pei, Bo Han, Hui-Gang Wei, Da-Wei Yuan, Gui-Yun Liang, Gang Zhao, Jia-Yong Zhong, Zhe Zhang, Bao-Jun Zhu, Yan-Fei Li, Fang Li, Yu-Tong Li, Si-Liang Zeng, Shi-Yang Zou, and Jie Zhang

    In this paper, the recent studies of laboratory astrophysics with strong magnetic fields in China have been reviewed. On the Shenguang-II laser facility of the National Laboratory on High-Power Lasers and Physics, a laser-driven strong magnetic field up to 200 T has been achieved. The experiment was performed to model the interaction of solar wind with dayside magnetosphere. Also the low beta plasma magnetic reconnection (MR) has been studied. Theoretically, the model has been developed to deal with the atomic structures and processes in strong magnetic field. Also the study of shock wave generation in the magnetized counter-streaming plasmas is introduced.

    Jan. 01, 1900
  • Vol. 4 Issue 3 03000e27 (2016)
  • Haixia An, Xiaogang Liu, and Zhiyue Bi

    Heat handling has been a significant problem of the high power fiber laser systems as the output power increases rapidly. Cladding power stripper (CPS) which is used to deal with the unwanted optical power and light is required for higher cooling ability. So the methods of stripping the unwanted light attracted much attention recently, and the thermal effect is given. However, few investigations focus on the dissipation of the heat converted from the unwanted light. In this paper,an approach of active cooling for CPS is demonstrated. This is achieved by using microchannel cooling technology in heat sinking in CPS to improve the efficiency of heat exchange. In order to explain the mechanism of CPS the function of it and consistence of categories of the unwanted light are detailed firstly. Then microchannel heat sinking is proposed and verified by the heat exchange theory. At last, the design of the CPS with microchannel heat sinking is shown and following experiment is conducted. The final temperature of the device with 1000 W cladding power was demonstrated at last to verify the ability of heat distribution of the CPS component. This suggests that these CPSs can be used to stripe a thousand of watts of light in high power double cladding fiber lasers.

    Jan. 01, 1900
  • Vol. 4 Issue 3 03000e28 (2016)
  • E. Brambrink, S. Baton, M. Koenig, R. Yurchak, N. Bidaut, B. Albertazzi, J. E. Cross, G. Gregori, A. Rigby, E. Falize, A. Pelka, F. Kroll, S. Pikuz, Y. Sakawa, N. Ozaki, C. Kuranz, M. Manuel, C. Li, P. Tzeferacos, and D. Lamb

    We have developed a new radiography setup with a short-pulse laser-driven x-ray source. Using a radiography axis perpendicular to both long- and short-pulse lasers allowed optimizing the incident angle of the short-pulse laser on the x-ray source target. The setup has been tested with various x-ray source target materials and different laser wavelengths. Signal to noise ratios are presented as well as achieved spatial resolutions. The high quality of our technique is illustrated on a plasma flow radiograph obtained during a laboratory astrophysics experiment on POLARs.

    Jan. 01, 1900
  • Vol. 4 Issue 3 03000e30 (2016)
  • Haitao Zhang, Xinglai Shen, He Hao, Qinghua Li, and Mali Gong

    High coherence of the laser is indispensable light sources in modern long or short-distance imaging systems, because the high coherence leads to coherent artifacts such as speckle that corrupt image formation. To deliver low coherence pulses in fiber amplifiers, we utilize the superluminescent pulsed light with broad bandwidth, nonlongitudinal mode structure and chaotic mode phase as the seed source of the cascaded fiber amplifiers. The influence of fiber superluminescent pulseamplification (SPA) on the limitations of the performance is analyzed. A review of our research results for SPA in the fibers are present, including the nonlinear theories of this low coherent light sources, i.e., self-focusing (SF), stimulated Raman scattering (SRS) and self-phase modulation (SPM) effects, and the experiment results of the nanosecond pulses with peak power as high as 4.8 MW and pulse energy as much as 55 mJ. To improve the brightness of SPA light in the future work, we introduce our novel evaluation term and a more reasonable criterion, which is denoted by a new parameter of brightness factor for active large mode area fiber designs. A core-doped active large pitch fiber with a core diameter of 190 mm and a mode-field diameter of 180 mm is designed by this method. The designed fiber allows neardiffracted limited beam quality operation, and it can achieve 100 mJ pulse energy and 540 Waverage power by analyzing the mode coupling effects induced by heat.

    Jan. 01, 1900
  • Vol. 4 Issue 3 03000e31 (2016)
  • Patrick Rambo, Jens Schwarz, Mark Kimmel, and John L. Porter

    We have developed high damage threshold filters to modify the spatial profile of a high energy laser beam. The filters are formed by laser ablation of a transmissive window. The ablation sites constitute scattering centers which can be filtered in a subsequent spatial filter. By creating the filters in dielectric materials, we see an increased laser-induced damage threshold from previous filters created using ‘metal on glass’ lithography.

    Jan. 01, 1900
  • Vol. 4 Issue 3 03000e32 (2016)
  • Bruno Gonzalez-Izquierdo, Ross J. Gray, Martin King, Robbie Wilson, Rachel J. Dance, Haydn Powell, David A. MacLellan, John McCreadie, Nicholas M. H. Butler, Steve Hawkes, James S. Green, Chris D. Murphy, Luca C. Stockhausen, David C. Carroll, Nicola Booth, Graeme G. Scott, Marco Borghesi, David Neely, and Paul McKenna

    The collective response of electrons in an ultrathin foil target irradiated by an ultraintense (6  1020 W cm??2) laser pulse is investigated experimentally and via 3D particle-in-cell simulations. It is shown that if the target is sufficiently thin that the laser induces significant radiation pressure, but not thin enough to become relativistically transparent to the laser light, the resulting relativistic electron beam is elliptical, with the major axis of the ellipse directed along the laser polarization axis. When the target thickness is decreased such that it becomes relativistically transparent early in the interaction with the laser pulse, diffraction of the transmitted laser light occurs through a so called ‘relativistic plasma aperture’, inducing structure in the spatial-intensity profile of the beam of energetic electrons. It is shown that the electron beam profile can be modified by variation of the target thickness and degree of ellipticity in the laser polarization.

    Jan. 01, 1900
  • Vol. 4 Issue 3 03000e33 (2016)
  • D.N. Papadopoulos, J.P. Zou, C. Le Blanc, G. Ch′eriaux, P. Georges, F. Druon, G. Mennerat, P. Ramirez, L. Martin, A. Fr′eneaux, A. Beluze, N. Lebas, P. Monot, F. Mathieu, and P. Audebert

    The objective of the Apollon 10 PW project is the generation of 10 PW peak power pulses of 15 fs at 1 shot min??1. In this paper a brief update on the current status of the Apollon project is presented, followed by a more detailed presentation of our experimental and theoretical investigations of the temporal characteristics of the laser. More specifically the design considerations as well as the technological and physical limitations to achieve the intended pulse duration and contrast are discussed.

    Jan. 01, 1900
  • Vol. 4 Issue 3 03000e34 (2016)
  • S. Eliezer, J. M. Martinez-Val, Z. Henis, N. Nissim, S. V. Pinhasi, A. Ravid, M. Werdiger, and E. Raicher

    The laser-induced relativistic shock waves are described. The shock waves can be created directly by a high irradiance laser or indirectly by a laser acceleration of a foil that collides with a second static foil. A special case of interest is the creation of laser-induced fusion where the created alpha particles create a detonation wave. A novel application is suggested with the shock wave or the detonation wave to ignite a pre-compressed target. In particular, the deuterium–tritium fusion is considered. It is suggested that the collision of two laser accelerated foils might serve as a novel relativistic accelerator for bulk material collisions.

    Jan. 01, 1900
  • Vol. 4 Issue 3 03000e25 (2016)
  • Jaebum Park, Hector A. Baldis, and Hui Chen

    We present an interferometry setup and the detailed fringe analysis method for intense short pulse (SP) laser experiments. The interferometry scheme was refined through multiple campaigns to investigate the effects of pre-plasmas on energetic electrons at the Jupiter Laser Facility at Lawrence Livermore National Laboratory. The interferometer used a frequency doubled ( D 0:527 mm) 0.5 ps long optical probe beam to measure the pre-plasma density, an invaluable parameter tobetter understand how varying pre-plasma conditions affect the characteristics of the energetic electrons. The hardware of the diagnostic, data analysis and example data are presented. The diagnostic setup and the analysis procedure can be employed for any other SP laser experiments and interferograms, respectively.finish the manuscript. This work was performed under the auspices of the US DOE by LLNL under contract no. DEAC52-07NA27344 and funded by the LDRD (12-ERD-062) program.

    Jan. 01, 1900
  • Vol. 4 Issue 3 03000e26 (2016)
  • Qun Zhang, and Yi Luo

    Over the past decade the integration of ultrafast spectroscopy with nanoscience has greatly propelled the development of nanoscience, as the key information gleaned from the mechanistic studies with the assistance of ultrafast spectroscopy enables a deeper understanding of the structure–function interplay and various interactions involved in the nanosystems. This mini-review presents an overview of the recent advances achieved in our ultrafast spectroscopy laboratory that address the ultrafast dynamics and related mechanisms in several representative nanomaterial complex systems by means of femtosecond time-resolved transient absorption spectroscopy.We attempt to convey instructive, consistent information regarding the important processes, pathways, dynamics, and interactions involved in the nanomaterial complex systems, most of which exhibit excellent performance in photocatalysis.

    Jan. 01, 1900
  • Vol. 4 Issue 3 03000e22 (2016)
  • J. E. Calvert, A. J. Palmer, I. V. Litvinyuk, and R. T. Sang

    The interactions of strong-field few-cycle laser pulses with metastable states of noble gas atoms are examined. Metastable noble gas atoms offer a combination of low ionization potential and a relatively simple atomic structure, making them excellent targets for examining ionization dynamics in varying experimental conditions. A review of the current work performed on metastable noble gas atoms is presented.

    Jan. 01, 1900
  • Vol. 4 Issue 3 03000e29 (2016)
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