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2016, 4(3) Column

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High Power Laser Science and Engineering 第4卷 第3期

Author Affiliations
Abstract
1 Laser Fusion Research Center, China Academy of Engineering Physics, P.O. Box 919-988, MianYang 621900, China
2 IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240, China
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.
inertial confinement fusion inertial confinement fusion laser driver laser driver SG-III SG-III 
High Power Laser Science and Engineering
2016, 4(3): 03000e21
Author Affiliations
Abstract
Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, PR China
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.
nanomaterials nanomaterials time-resolved femtosecond pump–probe time-resolved femtosecond pump–probe transient absorption spectroscopy transient absorption spectroscopy ultrafast dynamics ultrafast dynamics 
High Power Laser Science and Engineering
2016, 4(3): 03000e22
Author Affiliations
Abstract
1 LULI-UPMC Universit′e Paris 6: Sorbonne Universit′es, CNRS, Ecole Polytechnique, CEA: Universit′e Paris-Saclay, 75252 Paris, France
2 Institute of Physics of the ASCR, ELI-Beamlines, 18221 Prague, Czech Republic
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.
Brillouin backscattering Brillouin backscattering inertial confinement fusion inertial confinement fusion kinetic effects kinetic effects laser–plasma interaction laser–plasma interaction parametric instabilities parametric instabilities particlein-cell simulations particlein-cell simulations Raman backscattering Raman backscattering 
High Power Laser Science and Engineering
2016, 4(3): 03000e23
Author Affiliations
Abstract
Key Laboratory for Laser Plasmas (MOE) and Department of Physics and Astronomy, Collaborative Innovation Center of IFSA, Shanghai Jiao Tong University, Shanghai 200240, China
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.
ionization injection ionization injection laser–plasma acceleration laser–plasma acceleration PIC simulations PIC simulations self-truncation self-truncation wakefield wakefield 
High Power Laser Science and Engineering
2016, 4(3): 03000e24
Author Affiliations
Abstract
1 Institute of Nuclear Fusion, Polytechnic University of Madrid, Spain
2 Applied Physics Division, Soreq NRC Yavne, Israel
3 42 Beery, Rehovot, Israel
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.
fast ignition fast ignition laser piston model laser piston model relativistic shock waves relativistic shock waves ultra-intense lasers ultra-intense lasers 
High Power Laser Science and Engineering
2016, 4(3): 03000e25
Author Affiliations
Abstract
1 Lawrence Livermore National Laboratory, Livermore, CA 94551, USA
2 University of California, Davis, CA 95616, USA
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.
Mach–Zehnder interferometer Mach–Zehnder interferometer optical interferometry optical interferometry picosecond probe picosecond probe plasma density plasma density short pulse laser short pulse laser 
High Power Laser Science and Engineering
2016, 4(3): 03000e26
Author Affiliations
Abstract
1 Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China
2 University of Chinese Academy of Sciences, Beijing 100049, China
3 Department of Astronomy, Beijing Normal University, Beijing 100875, China
4 Beijing National Laboratory of Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
5 Institute of Applied Physics and Computational Mathematics, Beijing, 100088, China
6 Shanghai Jiao Tong University, Shanghai 200240, China
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.
Laboratory astrophysics Laboratory astrophysics laser laser strong magnetic fields strong magnetic fields 
High Power Laser Science and Engineering
2016, 4(3): 03000e27
Author Affiliations
Abstract
Institute of Systems Engineering, CAEP, Mianyang 621900, China
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.
cladding power stripper cladding power stripper double cladding fiber double cladding fiber high power laser system high power laser system microchannel microchannel 
High Power Laser Science and Engineering
2016, 4(3): 03000e28
Author Affiliations
Abstract
Australian Attosecond Science Facility, Center for Quantum Dynamics, School of Natural Sciences, Griffith University, Nathan, Queensland 4111, Australia
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.
COLTRIMS COLTRIMS electron holography electron holography high power lasers high power lasers ionization regime ionization regime metastable atoms metastable atoms spin polarized targets spin polarized targets 
High Power Laser Science and Engineering
2016, 4(3): 03000e29
E. Brambrink 1,2,*S. Baton 1,2M. Koenig 1,2,3R. Yurchak 1,2[ ... ]D. Lamb 12
Author Affiliations
Abstract
1 LULI - CNRS, Ecole Polytechnique, CEA : Universit′e Paris-Saclay
2 UPMC Univ Paris 06 : Sorbonne Universit′es - F-91128 Palaiseau cedex, France
3 Institute for Academic Initiatives, Osaka U., Suita, Osaka 565-0871, Japan
4 Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, UK
5 CEA-DAM-DIF, F-91297 Arpajon, France
6 HZDR, Bautzner Landstrae 400, 01328 Dresden, Germany
7 JIHT-RAS, 13-2 Izhorskaya st., Moscow, 125412, Russia
8 Institute of Laser Engineering, Osaka U., Suita, Osaka 565-0871, Japan
9 Graduate School of Engineering, Osaka U., Suita, Osaka 565-0871, Japan
10 Department of Energy Engineering Science, Faculty of Engineering Sciences, Kyushu University, Japan
11 Plasma Science and Fusion Center, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
12 Flash Center for Computational Science, University of Chicago, IL 60637, USA
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.
laboratory astrophysics laboratory astrophysics short-pulse laser short-pulse laser x-ray radiography x-ray radiography 
High Power Laser Science and Engineering
2016, 4(3): 03000e30
Author Affiliations
Abstract
Center for Photonics and Electronics, State Key Laboratory of Precision Measurement and Instruments, Department of Precision Instruments, Tsinghua University, Beijing, 100084, PR China
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.
superluminescent pulse amplification superluminescent pulse amplification fiber amplification fiber amplification incoherent incoherent nonlinear effects nonlinear effects very large mode field very large mode field 
High Power Laser Science and Engineering
2016, 4(3): 03000e31
Author Affiliations
Abstract
Sandia National Laboratories, PO Box 5800, MS 1197, Albuquerque, NM 87185, USA
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.
apodization apodization laser beam shaping laser beam shaping laser micro-machining laser micro-machining spatial filtering spatial filtering 
High Power Laser Science and Engineering
2016, 4(3): 03000e32
Author Affiliations
Abstract
1 SUPA Department of Physics, University of Strathclyde, Glasgow G4 0NG, UK
2 Central Laser Facility, STFC Rutherford Appleton Laboratory, Oxfordshire OX11 0QX, UK
3 Department of Physics, University of York, Heslington, York YO10 5DD, UK
4 Centro de L′aseres Pulsados (CLPU), M5 Parque Cient′?fico, 37185 Salamanca, Spain
5 Centre for Plasma Physics, Queens University Belfast, Belfast BT7 1NN, UK
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.
laser–plasmas interaction laser–plasmas interaction ultraintense ultraintense ultrashort pulse laser interaction with matters ultrashort pulse laser interaction with matters 
High Power Laser Science and Engineering
2016, 4(3): 03000e33
Author Affiliations
Abstract
1 Laboratoire pour l’Utilisation des Lasers Intenses, CNRS, Ecole Polytechnique, Palaiseau, France
2 Laboratoire Charles Fabry, UMR 8501 Institut d’Optique, CNRS, Univ Paris Sud, Palaiseau, France
3 CEA, Iramis, SPAM, Saclay, France
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.
high intensity lasers high intensity lasers spatiotemporal effects spatiotemporal effects ultrafast lasers ultrafast lasers 
High Power Laser Science and Engineering
2016, 4(3): 03000e34