High Power Laser Science and Engineering
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High Power Laser Science and Engineering 第3卷 第1期

Author Affiliations
Abstract
1 Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Republic of Korea
2 Department of Advanced Green Energy and Environment, Handong Global University, Heunghae-eup, Buk-gu, Pohang-si, Gyeongbuk 791-708, Republic of Korea
3 Laser Spectronix, 219 Gasan digital 1-ro, Geumcheon-gu, Seoul 153-704, Republic of Korea
In this review paper, we introduce a self-phase controlled stimulated Brillouin scattering phase conjugate mirror (SCSBS- PCM) and the Kumgang laser. The SC-SBS-PCM was proposed and demonstrated its success at the academic low power level, -100 mJ@10 Hz. The Kumgang laser is under development to verify whether the SC-SBS-PCM is operable at the kW level. It is a 4 kW beam combination laser combining four 1 kW beams using the SC-SBS-PCM. If the Kumgang laser functions successfully, it will be the most important step towards a Dream laser, a hypothetical laser with unlimited power and a high repetition rate.
coherent beam combination diode-pumped laser high-power laser self-phase controlled SBS-PCM 
High Power Laser Science and Engineering
2015, 3(1): 010000e1
Author Affiliations
Abstract
1 Laboratoire pour l’Utilisation des Lasers Intenses, CNRS, Ecole Polytechnique, Palaiseau, France
2 Laboratoire d’Optique Appliqu′ee, ENSTA ParisTech, CNRS, Palaiseau, France
3 Laboratoire Charles Fabry, UMR 8501, Institut d’Optique, CNRS, Universite Paris Sud, Palaiseau, France
4 CEA, Iramis, SPAM, Saclay, France
5 Laboratoire d’Optique Appliquee, ENSTA ParisTech, CNRS, Palaiseau, France
The objective of the Apollon project is the generation of 10 PW peak power pulses of 15 fs at 1 shot/minute. In this paper the Apollon facility design, the technological challenges and the current progress of the project will be presented.
titanium lasers PW class facilities 
High Power Laser Science and Engineering
2015, 3(1): 010000e2
Author Affiliations
Abstract
1 AWE, Aldermaston, Reading RG7 4PR, UK
2 STFC Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX, UK
The use of ultra-high intensity laser beams to achieve extreme material states in the laboratory has become almost routine with the development of the petawatt laser. Petawatt class lasers have been constructed for specific research activities, including particle acceleration, inertial confinement fusion and radiation therapy, and for secondary source generation (x-rays, electrons, protons, neutrons and ions). They are also now routinely coupled, and synchronized, to other large scale facilities including megajoule scale lasers, ion and electron accelerators, x-ray sources and z-pinches. The authors of this paper have tried to compile a comprehensive overview of the current status of petawatt class lasers worldwide. The definition of ‘petawatt class’ in this context is a laser that delivers >200 TW.
diode pumped high intensity high power lasers megajoule petawatt lasers 
High Power Laser Science and Engineering
2015, 3(1): 010000e3
Author Affiliations
Abstract
1 HiPER Project, STFC Rutherford Appleton Laboratory, UK
2 AWE plc, Aldermaston, UK
As our understanding of the environmental impact of fossil fuel based energy production increases, it is becoming clear that the world needs a new energy solution to meet the challenges of the future. A transformation is required in the energy market to meet the need for low carbon, sustainable, affordable generation matched with security of supply. In the short term, an increasing contribution from renewable sources may provide a solution in some locations. In the longer term, low carbon, sustainable solutions must be developed to meet base load energy demand, if the world is to avoid an ever increasing energy gap and the attendant political instabilities. Laser-driven inertial fusion energy (IFE) may offer such a solution.
ICF IFE inertial confinement fusion inertial fusion energy 
High Power Laser Science and Engineering
2015, 3(1): 010000e4
Author Affiliations
Abstract
1 National Laboratory on High Power Laser and Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
2 University of Chinese Academy of Sciences, Beijing 100049, China
In high-power laser systems (HPLSs), understanding debris-removal trajectories is important in eliminating debris from the surfaces of transport mirrors online and keeping other optical components free from contamination. NS equations, the RNG k–" model and the discrete phase model of the Euler–Lagrange method are used to conduct numerical simulations on the trajectories of contaminant particles of different sizes and types on the mirror surface using Fluent commercial software. A useful device is fabricated based on the simulation results. This device can capture and collect debris from the mirror surface online. Consequently, the effect of debris contamination on other optical components is avoided, cleaning time is shortened, and ultimately, the cleanliness of the mirrors in HPLSs is ensured.
cleanliness of the mirror debris trajectory Fluent high-power laser systems numerical simulations 
High Power Laser Science and Engineering
2015, 3(1): 010000e5
Author Affiliations
Abstract
1 Institute of Physics of the ASCR, ELI-Beamlines, 18221 Prague, Czech Republic
2 LULI, Sorbonne Universites-Universite Pierre et Marie Curie - Ecole Polytechnique - CNRS - CEA, 75005 Paris, France
The role of the coronal electron plasma temperature for shock-ignition conditions is analysed with respect to the dominant parametric processes: stimulated Brillouin scattering, stimulated Raman scattering, two-plasmon decay (TPD), Langmuir decay instability (LDI) and cavitation. TPD instability and cavitation are sensitive to the electron temperature. At the same time the reflectivity and high-energy electron production are strongly affected. For low plasma temperatures the LDI plays a dominant role in the TPD saturation. An understanding of laser–plasma interaction in the context of shock ignition is an important issue due to the localization of energy deposition by collective effects and hot electron production. This in turn can have consequences for the compression phase and the resulting gain factor of the implosion phase.
inertial confinement fusion shock ignition laser–plasma interaction parametric instabilities 
High Power Laser Science and Engineering
2015, 3(1): 010000e6
Author Affiliations
Abstract
1 Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, No. 390, Qinghe Road, Jiading District, Shanghai 201800, China
2 University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing 100049, China
The Shenguang-II Upgrade (SG-II Up) facility is an under-construction high-power laser driver with eight beams, 24 kJ energy, 3 ns pulse duration and ultraviolet laser output, in the Shanghai Institute of Optics and Fine Mechanics, China. The prototype design and experimental research of the prototype final optics assembly (FOA), which is one of the most important parts of the SG-II Up facility, have been completed on the ninth beam of the SG-II facility. Thirty-three shots were fired using 1-! energy from 1000 to 4500 J and 3-! energy from 500 to 2403 J with a 3 ns square pulse. During the experiments, emphasis was given to the process of optical damage and to the effects of clean-gas control. A numerical model of the FOA generated by the Integrated Computer Engineering and Manufacturing code for Computational Fluid Dynamics (ICEMCFD) demonstrated that a flux within 1–5 l s-1 and a 180 s period is effectual to avoid contaminant sputtering to the optics. The presence of surface ‘mooning’ damage and surface spots located outside the clear aperture are induced by contaminants such as wire, silica gel and millimeter order fiber and metal.
Final Optics Assembly optical damage SG-II-Up 
High Power Laser Science and Engineering
2015, 3(1): 010000e7
Author Affiliations
Abstract
1 Target Fabrication Group, Central Laser Facility, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot OX11 0QX, UK
2 Atomic and Laser Physics, Clarendon Laboratory, University of Oxford, OX1 3PU, UK
3 AWE, Aldermaston, Reading RG7 4PR, UK
4 CEA-DAM-DIF, F-91297 Arpajon, France
5 3
6 Laboratoire pour l’Utilisation Des Laser Intense, UMR 7605 CNRS-CEA-Ecole Polytechnique-Universit′e Paris VI, Palaiseau, France
This article describes the fabrication of a suite of laser targets by the Target Fabrication group in the Central Laser Facility (CLF), STFC Rutherford Appleton Laboratory for the first academic-access experiment on the Orion laser facility (Hopps et al., Appl. Opt. 52, 3597–3601 (2013)) at AtomicWeapons Establishment (AWE). This experiment, part of the POLAR project (Falize et al., Astrophys. Space Sci. 336, 81–85 (2011); Busschaert et al., New J. Phys. 15, 035020 (2013)), studied conditions relevant to the radiation-hydrodynamic processes occurring in a remarkable class of astrophysical star systems known as magnetic cataclysmic variables. A large number of complex fabrication technologies and research and development activities were required to field a total of 80 high-specification targets. Target design and fabrication procedures are described and initial alignment and characterization data are discussed.
astrophysics microtargets 
High Power Laser Science and Engineering
2015, 3(1): 010000e8
Author Affiliations
Abstract
Research Center of Laser Fusion, CAEP, P.O. Box 919-988, Mianyang 621900, China
Thermal stress can induce birefringence in a laser medium, which can cause depolarization of the laser. The depolarization effect will be very severe in a high-average-power laser. Because the depolarization will make the frequency doubling efficiency decline, it should be compensated. In this paper, the thermal characteristics of two kinds of materials are analyzed in respect of temperature, thermal deformation and thermal stress. The depolarization result from thermal stress was simulated. Depolarization on non-uniform pumping was also simulated, and the compensation method is discussed.
depolarization depolarization compensation thermal birefringence 
High Power Laser Science and Engineering
2015, 3(1): 010000e9
Author Affiliations
Abstract
Center for Relativistic Laser Science, Institute for Basic Science (IBS), Gwangju 500-712, Korea
Recently there has been great progress in laser-driven plasma-based accelerators by exploiting high-power lasers, where electron beams can be accelerated to multi-GeV energy in a centimeter-scale plasma due to the laser wakefield acceleration mechanism. While, to date, worldwide research on laser plasma accelerators has been focused on the creation of compact particle and radiation sources for basic sciences, medical and industrial applications, there is great interest in applications for high-energy physics and astrophysics, exploring unprecedented high-energy frontier phenomena. In this context, we present an overview of experimental achievements in laser plasma acceleration from the perspective of the production of GeV-level electron beams, and deduce the scaling formulas capable of predicting experimental results self-consistently, taking into account the propagation of a relativistic laser pulse through plasma and the accelerating field reduction due to beam loading. Finally, we present design examples for 10-GeV-level laser plasma acceleration, which is expected in near-term experiments by means of petawatt-class lasers.
electron beam loading GeV-level electron beam acceleration laser plasma (wakefield) accelerators petawatt-class lasers propagation of relativistic laser pulses in plasma 
High Power Laser Science and Engineering
2015, 3(1): 01000e10
Author Affiliations
Abstract
1 Signature Science, LLC, NJ 08234, USA
2 Department of Mechanical and Aerospace Engineering, Princeton University, NJ 08544, USA
We deduce a complete wave propagation equation that includes inhomogeneity of the dielectric constant and present this propagation equation in compact vector form. Although similar equations are known in narrow fields such as radio wave propagation in the ionosphere and electromagnetic and acoustic wave propagation in stratified media, we develop here a novel approach of using such equations in the modeling of laser beam propagation in nonlinear media. Our approach satisfies the correspondence principle since in the limit of zero-length wavelength it reduces from physical to geometrical optics.
light propagation self-focusing wavefront correction 
High Power Laser Science and Engineering
2015, 3(1): 01000e11
Author Affiliations
Abstract
1 Key Laboratory of Materials for High Power Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
2 University of Chinese Academy of Sciences, Beijing 100049, China
Rapid growth processing of KDP crystals was improved by employing continuous filtration to eliminate bulk defects. The performances of the KDP crystals, including scattering defects, laser damage resistance and transmittance, were measured and analyzed. Compared with rapid-grown KDP without continuous filtration, the transmittance in the nearinfrared was increased by at least 2%, almost all of ‘micron size’ defects were eliminated and ‘sub-micron size’ defects were decreased by approximately 90%. Laser damage testing revealed that the laser-induced damage thresholds (LIDTs), as well as the consistency of the LIDTs from sample to sample, were improved greatly. Moreover, it identified that ‘micron size’ defects were the precursors which initiated laser damage at relative lower laser fluence (4–6 J cm-2), and there was a lower correlation between smaller size scattering defects and laser damage initiation. The improved consistency in the LIDTs, attributed to elimination of ‘micron size’ defects, and LIDT enhancement originated from the decreased absorption of the KDP crystals.
continuous filtration defect KDP laser damage rapid growth 
High Power Laser Science and Engineering
2015, 3(1): 01000e13
Author Affiliations
Abstract
National Laboratory on High Power Laser and Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Science, Shanghai 201800, China
With the increasing number of laser beams, the main difficulty in arranging beam guiding systems (BGSs) involves determining the corresponding relationships between the output and input ports to realize the identified light path length of all beams. Given the basic constraints of geometric arrangement, a BGS model is established, and a base-line algorithm is proposed to address the difficulty mentioned above. Boundary conditions of target area and target chamber are discussed to increase the number of laser beams, and a maximum value exists for a specific target area. Finally, the compatibility of a cylindrical hohlraum target chamber with a spherical hohlraum is analyzed, and a moveable final optics assembly is proposed to execute the switch between the two different targets.
beam guiding system laser drivers spherical hohlraum target areas 
High Power Laser Science and Engineering
2015, 3(1): e12