High Power Laser Science and Engineering
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2023, 11(2) Column

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High Power Laser Science and Engineering 第11卷 第2期

Author Affiliations
Abstract
1 CEA CESTA, Le Barp, France
2 Aix-Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel, Marseille, France
Laser-induced damage (LID) on high-power laser facilities is one of the limiting factors for the increase in power and energy. Inertial confinement fusion (ICF) facilities such as Laser Mégajoule or the National Ignition Facility use spectral broadening of the laser pulse that may induce power modulations because of frequency modulation to amplitude modulation conversion. In this paper, we study the impact of low and fast power modulations of laser pulses both experimentally and numerically. The MELBA experimental testbed was used to shape a wide variety of laser pulses and to study their impact on LID. A 1D Lagrangian hydrodynamic code was used to understand the impact of different power profiles on LID.
fused silica high-power laser laser diagnostics laser-induced damage 
High Power Laser Science and Engineering
2023, 11(2): 02000e15
Author Affiliations
Abstract
High Power Laser Science and Engineering
2023, 11(2): 02000e16
Author Affiliations
Abstract
1 Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, Dresden, Germany
2 Technische Universität Dresden, Dresden, Germany
3 Key Laboratory of High Power Laser and Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai, China
4 Shanghai Institute of Laser Plasma, China Academy of Engineering Physics, Shanghai, China
5 Institute of Plasma Physics, Czech Academy of Sciences, Prague, Czech Republic
6 Czech Technical University, Faculty of Nuclear Sciences and Physical Engineering, Prague, Czech Republic
7 Department of Physics, Jagannath University, Dhaka, Bangladesh
8 ELI-Beamlines, Institute of Physics, Czech Academy of Sciences, Prague, Czech Republic
9 Institute for Nuclear Physics, Technical University of Darmstadt, Darmstadt, Germany
10 Institute of Physics, Czech Academy of Sciences, Prague, Czech Republic
11 Blackett Laboratory, Imperial College, London, United Kingdom
12 First Light Fusion, Oxford Industrial Park, Yarnton, Oxford, United Kingdom
A new approach to target development for laboratory astrophysics experiments at high-power laser facilities is presented. With the dawn of high-power lasers, laboratory astrophysics has emerged as a field, bringing insight into physical processes in astrophysical objects, such as the formation of stars. An important factor for success in these experiments is targetry. To date, targets have mainly relied on expensive and challenging microfabrication methods. The design presented incorporates replaceable machined parts that assemble into a structure that defines the experimental geometry. This can make targets cheaper and faster to manufacture, while maintaining robustness and reproducibility. The platform is intended for experiments on plasma flows, but it is flexible and may be adapted to the constraints of other experimental setups. Examples of targets used in experimental campaigns are shown, including a design for insertion in a high magnetic field coil. Experimental results are included, demonstrating the performance of the targets.
high magnetic fields laboratory astrophysics laser–plasma interaction magnetized plasmas target design 
High Power Laser Science and Engineering
2023, 11(2): 02000e17
Author Affiliations
Abstract
1 Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, China
2 Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai, China
The phase summation effect in sum-frequency mixing process is utilized to avoid a nonlinearity obstacle in the power scaling of single-frequency visible or ultraviolet lasers. Two single-frequency fundamental lasers are spectrally broadened by phase modulation to suppress stimulated Brillouin scattering in fiber amplifier and achieve higher power. After sum-frequency mixing in a nonlinear optical crystal, the upconverted laser returns to single frequency due to phase summation, when the phase modulations on two fundamental lasers have a similar amplitude but opposite sign. The method was experimentally proved in a Raman fiber amplifier-based laser system, which generated a power-scalable sideband-free single-frequency 590 nm laser. The proposal manifests the importance of phase operation in wave-mixing processes for precision laser technology.
high power phase summation single-frequency laser stimulated Brillouin scattering sum-frequency generation 
High Power Laser Science and Engineering
2023, 11(2): 02000e18
Author Affiliations
Abstract
1 Department of Physics, University of Gothenburg, Gothenburg, Sweden
2 Lawrence Berkeley National Laboratory, Berkeley, California, USA
3 Higgs Centre, School of Physics and Astronomy, University of Edinburgh, Edinburgh, UK
The availability of ever stronger, laser-generated electromagnetic fields underpins continuing progress in the study and application of nonlinear phenomena in basic physical systems, ranging from molecules and atoms to relativistic plasmas and quantum electrodynamics. This raises the question: how far will we be able to go with future lasers? One exciting prospect is the attainment of field strengths approaching the Schwinger critical field ${E}_{\mathrm{cr}}$ in the laboratory frame, such that the field invariant ${E}^2-{c}^2{B}^2>{E}_{\mathrm{cr}}^2$ is reached. The feasibility of doing so has been questioned, on the basis that cascade generation of dense electron–positron plasma would inevitably lead to absorption or screening of the incident light. Here we discuss the potential for future lasers to overcome such obstacles, by combining the concept of multiple colliding laser pulses with that of frequency upshifting via a tailored laser–plasma interaction. This compresses the electromagnetic field energy into a region of nanometre size and attosecond duration, which increases the field magnitude at fixed power but also suppresses pair cascades. Our results indicate that laser facilities with peak power of tens of PW could be capable of reaching ${E}_{\mathrm{cr}}$ . Such a scenario opens up prospects for the experimental investigation of phenomena previously considered to occur only in the most extreme environments in the universe.
Schwinger effect advanced focusing concepts attosecond pulses dipole wave surface high-order harmonic generation 
High Power Laser Science and Engineering
2023, 11(2): 02000e19
Author Affiliations
Abstract
1 Institute of Laser Engineering, Osaka University, Suita, Japan
2 National Institutes for Quantum Science and Technology, Tokai, Japan
3 Tokamak Energy Ltd., Abingdon, UK
4 Graduate School of Engineering, Osaka University, Suita, Japan
5 Fukui University of Technology, Fukui, Japan
We predict the production yield of a medical radioisotope ${}^{67}$ Cu using ${}^{67}$ Zn(n, p) ${}^{67}$ Cu and ${}^{68}$ Zn(n, pn) ${}^{67}$ Cu reactions with fast neutrons provided from laser-driven neutron sources. The neutrons were generated by the p+ ${}^9\mathrm{Be}$ and d+ ${}^9$ Be reactions with high-energy ions accelerated by laser–plasma interaction. We evaluated the yield to be (3.3 $\pm$ 0.5) $\times$ 10 ${}^5$ atoms for ${}^{67}$ Cu, corresponding to a radioactivity of 1.0 $\pm$ 0.2 Bq, for a Zn foil sample with a single laser shot. Using a simulation with this result, we estimated ${}^{67}$ Cu production with a high-frequency laser. The result suggests that it is possible to generate ${}^{67}$ Cu with a radioactivity of 270 MBq using a future laser system with a frequency of 10 Hz and 10,000-s radiation in a hospital.
laser ion acceleration laser-driven neutron source medical radioisotope 
High Power Laser Science and Engineering
2023, 11(2): 02000e20
Author Affiliations
Abstract
1 School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, China
2 Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai, China
Parametric interaction allows both forward and backward energy transfers among the three interacting waves. The back-conversion effect is usually detrimental when unidirectional energy transfer is desired. In this theoretical work, we manifest that the back-conversion effect underpins the direct generation of the picosecond pulse train without the need for a laser resonator. The research scenario is an optical parametric amplification (OPA) that consists of a second-order nonlinear medium, a quasi-continuous pump laser and a sinusoidal amplitude-modulated seed signal. The back-conversion of OPA can transfer the modulation peaks (valleys) of the incident signal into output valleys (peaks), which inherently induces spectral sidebands. The generation of each sideband is naturally accompanied with a phase shift of ±π. In the regime of full-back-conversion, the amount and amplitude of the sidebands reach the maximum simultaneously, and their phase constitutes an arithmetic sequence, leading to the production of a picosecond pulse train. The generated picosecond pulse train can have an ultrahigh repetition rate of 40 GHz or higher, which may facilitate ultrafast applications with ultrahigh speed.
picosecond pulse train quadratic parametric process sideband generation 
High Power Laser Science and Engineering
2023, 11(2): 02000e21
Jiexi Zuo 1,2,3,4Haijuan Yu 1,2,3,4Shuzhen Zou 1,4Zhiyong Dong 1,4[ ... ]Xuechun Lin 1,2,3,4,*
Author Affiliations
Abstract
1 Laboratory of All-Solid-State Light Sources, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, China
2 Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, China
3 College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing, China
4 Beijing Engineering Technology Research Center of All-Solid-State Lasers Advanced Manufacturing, Beijing, China
Achieving an all-fiber ultra-fast system with above kW average power and mJ pulse energy is extremely challenging. This paper demonstrated a picosecond monolithic master oscillator power amplifier system at a 25 MHz repetition frequency with an average power of approximately 1.2 kW, a pulse energy of approximately 48 μJ and a peak power of approximately 0.45 MW. The nonlinear effects were suppressed by adopting a dispersion stretched seed pulse (with a narrow linewidth of 0.052 nm) and a multi-mode master amplifier with an extra-large mode area; then an ultimate narrow bandwidth of 1.32 nm and a moderately broadened pulse of approximately 107 ps were achieved. Meanwhile, the great spatio-temporal stability was verified experimentally, and no sign of transverse mode instability appeared even at the maximum output power. The system has shown great power and energy capability with a sacrificed beam propagation product of 5.28 mm $\cdot$ mrad. In addition, further scaling of the peak power and pulse energy can be achieved by employing a lower repetition and a conventional compressor.
fiber laser nonlinear optics picosecond pulse transverse mode instability 
High Power Laser Science and Engineering
2023, 11(2): 02000e22
Author Affiliations
Abstract
1 John Adams Institute for Accelerator Science, Blackett Laboratory, Imperial College London, London, UK
2 School of Maths and Physics, Queen’s University Belfast, Belfast, UK
3 Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot, UK
4 SLAC National Accelerator Laboratory, Menlo Park, USA
5 ELI Beamlines Centre, Institute of Physics, CAS, Dolni Brezany, Czech Republic
6 Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Prague, Czech Republic
7 Department of Physics, SUPA, University of Strathclyde, Glasgow, UK
8 Department of Mechanical Engineering, Stanford University, Stanford, USA
9 Department of Applied Physics, Stanford University, Stanford, USA
10 Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Canada
11 Institut für Kernphysik, Technische Universität Darmstadt, Darmstadt, Germany
We present the development and characterization of a high-stability, multi-material, multi-thickness tape-drive target for laser-driven acceleration at repetition rates of up to 100 Hz. The tape surface position was measured to be stable on the sub-micrometre scale, compatible with the high-numerical aperture focusing geometries required to achieve relativistic intensity interactions with the pulse energy available in current multi-Hz and near-future higher repetition-rate lasers ( $>$ kHz). Long-term drift was characterized at 100 Hz demonstrating suitability for operation over extended periods. The target was continuously operated at up to 5 Hz in a recent experiment for 70,000 shots without intervention by the experimental team, with the exception of tape replacement, producing the largest data-set of relativistically intense laser–solid foil measurements to date. This tape drive provides robust targetry for the generation and study of high-repetition-rate ion beams using next-generation high-power laser systems, also enabling wider applications of laser-driven proton sources.
high-repetition-rate laser target laser–plasma acceleration proton generation tape-drive target 
High Power Laser Science and Engineering
2023, 11(2): 02000e23
Author Affiliations
Abstract
1 Intense Laser Irradiation Laboratory, INO-CNR, Pisa, Italy
2 Dipartimento SBAI, Università di Roma ‘La Sapienza’, Roma, Italy
3 Université Bordeaux, CNRS, CEA, CELIA, Talence, France
4 Institute of Laser Engineering, Osaka University, Osaka, Japan
5 Centre de Physique Théorique CPHT, CNRS, IP Paris, Ecole Polytechnique, Palaiseau, France
6 Graduate School of Engineering, Osaka University, Osaka, Japan
7 Institute of Plasma Physics and Lasers, Hellenic Mediterranean University Research Centre, Rethymnon, Greece
8 Institute for Integrated Radiation and Nuclear Science, Kyoto University, Sennan, Osaka, Japan
Laser–plasma interaction and hot electrons have been characterized in detail in laser irradiation conditions relevant for direct-drive inertial confinement fusion. The experiment was carried out at the Gekko XII laser facility in multibeam planar target geometry at an intensity of approximately $3\times {10}^{15}$ W/cm2. Experimental data suggest that high-energy electrons, with temperatures of 20–50 keV and conversion efficiencies of $\eta <1\%$ , were mainly produced by the damping of electron plasma waves driven by two-plasmon decay (TPD). Stimulated Raman scattering (SRS) is observed in a near-threshold growth regime, producing a reflectivity of approximately $0.01\%$ , and is well described by an analytical model accounting for the convective growth in independent speckles. The experiment reveals that both TPD and SRS are collectively driven by multiple beams, resulting in a more vigorous growth than that driven by single-beam laser intensity.
inertial confinement fusion laser plasma interaction parametric instabilities 
High Power Laser Science and Engineering
2023, 11(2): 02000e24
Author Affiliations
Abstract
College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha, China
An all-fiber high-power linearly polarized chirped pulse amplification (CPA) system is experimentally demonstrated. Through stretching the pulse duration to a full width of approximately 2 ns with two cascaded chirped fiber Bragg gratings (CFBGs), a maximum average output power of 612 W is achieved from a high-gain Yb-doped fiber that has a core diameter of 20 μm with a slope efficiency of approximately 68% at the repetition rate of 80 MHz. At the maximum output power, the polarization degree is 92.5% and the M2 factor of the output beam quality is approximately 1.29; the slight performance degradations are attributed to the thermal effects in the main amplifier. By optimizing the B-integral of the amplifier and finely adjusting the higher-order dispersion of one of the CFBGs, the pulse width is compressed to 863 fs at the highest power with a compression efficiency of 72%, corresponding to a maximum compressed average power of 440.6 W, single pulse energy of 5.5 μJ and peak power of about 4.67 MW. To the best of our knowledge, this is the highest average power of a femtosecond laser directly generated from an all-fiber linearly polarized CPA system.
chirped pulse amplification femtosecond laser fiber laser high-power laser ultrafast laser 
High Power Laser Science and Engineering
2023, 11(2): 02000e25
Author Affiliations
Abstract
1 State Key Laboratory of High Field Laser Physics and CAS Center for Excellence in Ultra-intense Laser Science, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai, China
2 Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, China
3 Department of Physics, Shanghai Normal University, Shanghai, China
Laser-accelerated electrons are promising in producing gamma-photon beams of high peak flux for the study of nuclear photonics, obtaining copious positrons and exploring photon–photon interaction in vacuum. We report on the experimental generation of brilliant gamma-ray beams with not only high photon yield but also low divergence, based on picosecond laser-accelerated electrons. The 120 J 1 ps laser pulse drives self-modulated wakefield acceleration in a high-density gas jet and generates tens-of-MeV electrons with 26 nC and divergence as small as $1.51{}^{\circ}$ . These collimated electrons produce gamma-ray photons through bremsstrahlung radiation when transversing a high-Z solid target. We design a high-energy-resolution Compton-scattering spectrometer and find that a total photon number of $2.2\times {10}^9$ is captured within an acceptance angle of $1.1{}^{\circ}$ for photon energies up to $16\;\mathrm{MeV}$ . Comparison between the experimental results and Monte Carlo simulations illustrates that the photon beam inherits the small divergence from electrons, corresponding to a total photon number of $2.2\times {10}^{11}$ and a divergence of $7.73{}^{\circ}$ .
bremsstrahlung Compton scattering gamma-ray beam laser-electron acceleration spectrometer 
High Power Laser Science and Engineering
2023, 11(2): 02000e26
Author Affiliations
Abstract
Solid State Laser Laboratory, Center for Physical Sciences and Technology, Vilnius, Lithuania
We present a compact and cost-effective mJ-level femtosecond laser system operating at a center wavelength of approximately 2.15 μm. An affordable two-stage ytterbium-doped yttrium aluminum garnet (Yb:YAG) chirped pulse amplifier provides more than 10 mJ, approximately 1.2 ps pulses at 1030 nm to pump a three-stage optical parametric chirped pulse amplifier (OPCPA) based on bismuth borate crystals and to drive the supercontinuum seed in the YAG crystal. The energy of the amplified pulses in the wavelength range of 1.95–2.4 μm reached 2.25 mJ with a pump-to-signal conversion efficiency of approximately 25% in the last OPCPA stage. These pulses were compressed to 38 fs in a pair of Suprasil 300 glass prisms.
mid-infrared optical parametric chirped pulse amplifier short infrared supercontinuum ytterbium-doped yttrium aluminum garnet 
High Power Laser Science and Engineering
2023, 11(2): 02000e27
Author Affiliations
Abstract
Institute of Applied Physics of the Russian Academy of Sciences, Nizhny Novgorod, Russia
It was shown experimentally that for a 65-fs 17-J pulse, the effect of filamentation instability, also known as small-scale self-focusing, is much weaker than that predicted by stationary and nonstationary theoretical models for high B-integral values. Although this discrepancy has been left unexplained at the moment, in practice no signs of filamentation may allow a breakthrough in nonlinear pulse post-compression at high laser energy.
B-integral cubic Kerr nonlinearity filamentation instability high-power femtosecond laser nonlinear post-compression 
High Power Laser Science and Engineering
2023, 11(2): 02000e28
Author Affiliations
Abstract
1 State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, China
2 The 41st Institute of China Electronics Technology Group Corporation, Qingdao, China
We report a compact, tunable, self-starting, all-fiber laser-based asynchronous optical sampling (ASOPS) system. Two Er-doped fiber oscillators were used as the pulsed-laser source, whose repetition rate could be set at 100 MHz with a tuning range of 1.25 MHz through a fiber delay line. By employing phase-locked and temperature control loops, the repetition rate offset of the two lasers was stabilized with 7.13 × 10-11 fractional instability at an average time of 1 s. Its capabilities in the terahertz regime were demonstrated by terahertz time-domain spectroscopy, achieving a spectral bandwidth of 3 THz with a dynamic range of 30 dB. The large range of repetition rate adjustment in our ASOPS system has the potential to be a powerful tool in the terahertz regime.
asynchronous optical sampling mode-locked fiber laser terahertz time-domain spectroscopy 
High Power Laser Science and Engineering
2023, 11(2): 02000e29
Author Affiliations
Abstract
1 LULI-CNRS, CEA, Universite Sorbonne, Ecole Polytechnique, Institut Polytechnique de Paris, Palaiseau CEDEX, France
2 Doctoral School of Physics, University of Bucharest, Bucharest-Magurele, Romania
3 Horia Hulubei National Institute for R&D in Physics and Nuclear Engineering (IFIN-HH), Magurele, Romania
4 IZEST, Ecole Polytechnique, Institut Polytechnique de Paris, Palaiseau CEDEX, France
5 Independent Researcher, Bourg-La-Reine, France
6 Federal Research Center Institute of Applied Physics of the Russian Academy of Sciences (IAP RAS), Nizhny Novgorod, Russia
The post-compression technique based on self-phase modulation of high-energy pulses leads to an increase in achievable peak power and intensity. Typically, the pulses considered in experiments have been less than 100 fs in duration. Here, the method is applied to the ELFIE laser system at the LULI facility, for a pulse of 7 J energy and an initial measured duration of 350 fs. A 5-mm-thick fused silica window and a 2 mm cyclic-olefin polymer were used as optical nonlinear materials. The 9 cm diameter beam was spectrally broadened to a bandwidth corresponding to 124 fs Fourier-limited pulse duration, and then it was partly post-compressed to 200 fs. After measuring the spatial spectra of the beam fluence, a uniform gain factor of 4 increase in the fluctuations over the studied range of frequencies is observed, due to small-scale self-focusing.
high-power laser nonlinear pulse interaction post-compression self-phase modulation 
High Power Laser Science and Engineering
2023, 11(2): 02000e30
Ning Wen 1,3,5Nan Wang 2Nan Zong 1,3,4,*Xue-Chun Lin 2,*[ ... ]Zu-Yan Xu 1,3,4
Author Affiliations
Abstract
1 Key Laboratory of Functional Crystal and Laser Technology, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, China
2 Laboratory of All-Solid-State Light Source, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, China
3 Key Laboratory of Solid-State Laser, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, China
4 Institute of Optical Physics and Engineering Technology, Qilu Zhongke, Jinan, China
5 University of Chinese Academy of Sciences, Beijing, China
We present a high-energy, hundred-picosecond (ps) pulsed mid-ultraviolet solid-state laser at 266 nm by a direct second harmonic generation (SHG) in a barium borate (BaB2O4, BBO) nonlinear crystal. The green pump source is a 710 mJ, 330 ps pulsed laser at a wavelength of 532 nm with a repetition rate of 1 Hz. Under a green pump energy of 710 mJ, a maximum output energy of 253.3 mJ at 266 nm is achieved with 250 ps pulse duration resulting in a peak power of more than 1 GW, corresponding to an SHG conversion efficiency of 35.7% from 532 to 266 nm. The experimental data were well consistent with the theoretical prediction. To the best of our knowledge, this laser exhibits both the highest output energy and highest peak power ever achieved in a hundred-ps/ps regime at 266 nm for BBO-SHG.
all-solid-state laser hundred-picosecond pulse mid-ultraviolet high-energy laser 
High Power Laser Science and Engineering
2023, 11(2): 02000e31