Journals >High Power Laser Science and Engineering
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2021
Volume: 9 Issue 4
19 Article(s)
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HIGH ENERGY DENSITY PHYSICS AND HIGH POWER LASERS
High-intensity laser-driven secondary radiation sources using the ZEUS 45 TW laser system at the Institute of Plasma Physics and Lasers of the Hellenic Mediterranean University Research Centre
E. L. Clark, A. Grigoriadis, S. Petrakis, I. Tazes, G. Andrianaki, A. Skoulakis, Y. Orphanos, E. Kaselouris, I. Fitilis, J. Chatzakis, E. Bakarezos, V. Dimitriou, E. P. Benis, N. A. Papadogiannis, and M. Tatarakis
The rapid development of high-intensity laser-generated particle and photon secondary sources has attracted widespread interest during the last 20 years not only due to fundamental science research but also because of the important applications of this developing technology. For instance, the generation of relativisticThe rapid development of high-intensity laser-generated particle and photon secondary sources has attracted widespread interest during the last 20 years not only due to fundamental science research but also because of the important applications of this developing technology. For instance, the generation of relativistic particle beams, betatron-type coherent X-ray radiation and high harmonic generation have attracted interest from various fields of science and technology owing to their diverse applications in biomedical, material science, energy, space, and security applications. In the field of biomedical applications in particular, laser-driven particle beams as well as laser-driven X-ray sources are a promising field of study. This article looks at the research being performed at the Institute of Plasma Physics and Lasers (IPPL) of the Hellenic Mediterranean University Research Centre. The recent installation of the ZEUS 45 TW laser system developed at IPPL offers unique opportunities for research in laser-driven particle and X-ray sources. This article provides information about the facility and describes initial experiments performed for establishing the baseline platforms for secondary plasma sources..
High Power Laser Science and Engineering
- Publication Date: Jan. 01, 1900
- Vol. 9, Issue 4, 04000e53 (2021)
2-kW-level superfluorescent fiber source with flexible wavelength and linewidth tunable characteristics
Jun Ye, Chenchen Fan, Jiangming Xu, Hu Xiao, Jinyong Leng, and Pu Zhou
The superfluorescent fiber source (SFS) with tunable optical spectrum has shown great application potential in the sensing, imaging, and spectral combination. Here, we demonstrate for the first time a 2-kW-level wavelength and linewidth tunable SFS. Based on a flexible filtered SFS seed and three stages of fiber amplifThe superfluorescent fiber source (SFS) with tunable optical spectrum has shown great application potential in the sensing, imaging, and spectral combination. Here, we demonstrate for the first time a 2-kW-level wavelength and linewidth tunable SFS. Based on a flexible filtered SFS seed and three stages of fiber amplifiers, the output power can be scaled from the milliwatt level to about 2 kW, with a wavelength tuning range of 1068–1092 nm and a linewidth tuning range of 2.5–9.7 nm. Moreover, a numerical simulation is conducted based on the generalized nonlinear Schrödinger equation, and the results reveal that the wavelength tuning range is limited by the decrease of seed power and the growth of amplified spontaneous emission, whereas the linewidth tuning range is determined by the gain competition and nonlinear Kerr effects. The developed wavelength and linewidth tunable SFS may be applied to scientific research and industrial processing..
High Power Laser Science and Engineering
- Publication Date: Jan. 01, 1900
- Vol. 9, Issue 4, 04000e55 (2021)
Static and dynamic mode evolution in high-power distributed side-coupled cladding-pumped fiber amplifiers
Rumao Tao, Yu Liu, Lianghua Xie, Cong Gao, Min Li, Benjian Shen, Shan Huang, Honghuan Lin, Jianjun Wang, and Feng Jing
We present a theoretical study of mode evolution in high-power distributed side-coupled cladding-pumped (DSCCP) fiber amplifiers. A semi-analytical model taking the side-pumping schemes, transverse mode competition, and stimulated thermal Rayleigh scattering into consideration has been built, which can model the staticWe present a theoretical study of mode evolution in high-power distributed side-coupled cladding-pumped (DSCCP) fiber amplifiers. A semi-analytical model taking the side-pumping schemes, transverse mode competition, and stimulated thermal Rayleigh scattering into consideration has been built, which can model the static and dynamic mode evolution in high-power DSCCP fiber amplifiers. The mode evolution behavior has been investigated with variation of the fiber amplifier parameters, such as the pump power distribution, the length of the DSCCP fiber, the averaged coupling coefficient, the number of the pump cores and the arrangement of the pump cores. Interestingly, it revealed that static mode evolution induced by transverse mode competition is different from the dynamic evolution induced by stimulated thermal Rayleigh scattering. This shows that the high-order mode experiences a slightly higher gain in DSCCP fiber amplifiers, but the mode instability thresholds for DSCCP fiber amplifiers are higher than those for their end-coupled counterparts. By increasing the pump core number and reducing the averaged coupling coefficient, the mode instability threshold can be increased, which indicates that DSCCP fibers can provide additional mitigation strategies of dynamic mode instability..
High Power Laser Science and Engineering
- Publication Date: Jan. 01, 1900
- Vol. 9, Issue 4, 04000e58 (2021)
Enhancement of pre-pulse and picosecond pedestal contrast of the petawatt J-KAREN-P laser
Hiromitsu Kiriyama, Yasuhiro Miyasaka, Akira Kon, Mamiko Nishiuchi, Akito Sagisaka, Hajime Sasao, Alexander S. Pirozhkov, Yuji Fukuda, Koichi Ogura, Kotaro Kondo, Nicholas P. Dover, and Masaki Kando
We have experimentally improved the temporal contrast of the petawatt J-KAREN-P laser facility. We have investigated how the generation of pre-pulses by post-pulses changes due to the temporal overlap between the stretched pulse and the post-pulse in a chirped-pulse amplification system. We have shown that the time at We have experimentally improved the temporal contrast of the petawatt J-KAREN-P laser facility. We have investigated how the generation of pre-pulses by post-pulses changes due to the temporal overlap between the stretched pulse and the post-pulse in a chirped-pulse amplification system. We have shown that the time at which the pre-pulse is generated by the post-pulse and its shape are related to the time difference between the stretched main pulse and the post-pulse. With this investigation, we have found and identified the origins of the pre-pulses and have demonstrated the removal of most pre-pulses by eliminating the post-pulse with wedged optics. We have also demonstrated the impact of stretcher optics on the picosecond pedestal. We have realized orders of magnitude enhancement of the pedestal by improving the optical quality of a key component in the stretcher..
High Power Laser Science and Engineering
- Publication Date: Jan. 01, 1900
- Vol. 9, Issue 4, 04000e62 (2021)
MTW-OPAL: a technology development platform for ultra-intense optical parametric chirped-pulse amplification systems | On the Cover
J. Bromage, S.-W. Bahk, M. Bedzyk, I. A. Begishev, S. Bucht, C. Dorrer, C. Feng, C. Jeon, C. Mileham, R. G. Roides, K. Shaughnessy, M. J. Shoup, M. Spilatro, B. Webb, D. Weiner, and J. D. Zuegel
Optical parametric chirped-pulse amplification implemented using multikilojoule Nd:glass pump lasers is a promising approach for producing ultra-intense pulses (>1023 W/cm2). We report on the MTW-OPAL Laser System, an optical parametric amplifier line (OPAL) pumped by the Nd:doped portion of the multi-terawatt (MTW)Optical parametric chirped-pulse amplification implemented using multikilojoule Nd:glass pump lasers is a promising approach for producing ultra-intense pulses (>1023 W/cm2). We report on the MTW-OPAL Laser System, an optical parametric amplifier line (OPAL) pumped by the Nd:doped portion of the multi-terawatt (MTW) laser. This midscale prototype was designed to produce 0.5-PW pulses with technologies scalable to tens of petawatts. Technology choices made for MTW-OPAL were guided by the longer-term goal of two full-scale OPALs pumped by the OMEGA EP to produce 2 × 25-PW beams that would be co-located with kilojoule-nanosecond ultraviolet beams. Several MTW-OPAL campaigns that have been completed since “first light” in March 2020 show that the laser design is fundamentally sound, and optimization continues as we prepare for “first-focus” campaigns later this year..
High Power Laser Science and Engineering
- Publication Date: Jan. 01, 1900
- Vol. 9, Issue 4, 04000e63 (2021)
Transient electromagnetic fields generated in experiments at the PHELIX laser facility
M. Scisciò, F. Consoli, M. Salvadori, N. E. Andreev, N. G. Borisenko, S. Zähter, and O. Rosmej
Large-amplitude electromagnetic radiofrequency fields are created by the charge-separation induced in interactions of high-intensity, short-pulse lasers with solid targets and have intensity that decreases with the distance from the target. Alternatively, it was experimentally proved very recently that charged particleLarge-amplitude electromagnetic radiofrequency fields are created by the charge-separation induced in interactions of high-intensity, short-pulse lasers with solid targets and have intensity that decreases with the distance from the target. Alternatively, it was experimentally proved very recently that charged particles emitted by petawatt laser–target interactions can be deposited on a capacitor-collector structure, far away from the target, and lead to the rapid (nanosecond-scale) generation of large quasi-static electric fields ($\mathrm{MV}/\mathrm{m}$ ), over wide regions. We demonstrate here the generation of both these fields in experiments at the PHELIX laser facility, with approximately $20\;\mathrm{J}$ energy and approximately ${10}^{19}\;\mathrm{W}/\mathrm{c}{\mathrm{m}}^2$ intensity, for picoseconds laser pulses, interacting with pre-ionized polymer foams of near critical density. Quasi-static fields, up to tens of kV/m, were here observed at distances larger than $1\;\mathrm{m}$ from the target, with results much higher than the radiofrequency component. This is of primary importance for inertial-confinement fusion and laser–plasma acceleration and also for promising applications in different scenarios..
High Power Laser Science and Engineering
- Publication Date: Jan. 01, 1900
- Vol. 9, Issue 4, 04000e64 (2021)
XFELS
Overview of SwissFEL dual-photocathode laser capabilities and perspectives for exotic FEL modes
S. Bettoni, A. Cavalieri, A. Dax, E. Divall, C. P. Hauri, S. Hunziker, M. Huppert, M. Kaiser, M. Paraliev, C. Sydlo, C. Vicario, and A. Trisorio
SwissFEL is a compact, high-brilliance, soft and hard X-ray free electron laser (FEL) facility that started user operation in 2019. The facility is composed of two parallel beam lines seeded by a common linear accelerator (LINAC), and a two-bunch photo-injector. For the injector, an innovative dual-photocathode laser sSwissFEL is a compact, high-brilliance, soft and hard X-ray free electron laser (FEL) facility that started user operation in 2019. The facility is composed of two parallel beam lines seeded by a common linear accelerator (LINAC), and a two-bunch photo-injector. For the injector, an innovative dual-photocathode laser scheme has been developed based on state-of-the-art ytterbium femtosecond laser systems. In this paper, we describe the performance of the SwissFEL photocathode drive lasers (PCDLs), the pulse-shaping capabilities as well as the versatility of the systems, which allow many different modes of operation of SwissFEL. The full control over the SwissFEL electron bunch properties via the unique architecture of the PCDLs will enable in the future the advent of more-advanced FEL modes; these modes include, but are not restricted to, the generation of single or trains of sub-femtosecond FEL pulses, multi-color FEL and finally, the generation of fully coherent X-ray pulses via laser-based seeding..
High Power Laser Science and Engineering
- Publication Date: Jan. 01, 1900
- Vol. 9, Issue 4, 04000e51 (2021)
Free electron lasers driven by plasma accelerators: status and near-term prospects
C. Emma, J. Van Tilborg, R. Assmann, S. Barber, A. Cianchi, S. Corde, M. E. Couprie, R. D’Arcy, M. Ferrario, A. F. Habib, B. Hidding, M. J. Hogan, C. B. Schroeder, A. Marinelli, M. Labat, R. Li, J. Liu, A. Loulergue, J. Osterhoff, A. R. Maier, B. W. J. McNeil, and W. Wang
Owing to their ultra-high accelerating gradients, combined with injection inside micrometer-scale accelerating wakefield buckets, plasma-based accelerators hold great potential to drive a new generation of free-electron lasers (FELs). Indeed, the first demonstration of plasma-driven FEL gain was reported recently, reprOwing to their ultra-high accelerating gradients, combined with injection inside micrometer-scale accelerating wakefield buckets, plasma-based accelerators hold great potential to drive a new generation of free-electron lasers (FELs). Indeed, the first demonstration of plasma-driven FEL gain was reported recently, representing a major milestone for the field. Several groups around the world are pursuing these novel light sources, with methodology varying in the use of wakefield driver (laser-driven or beam-driven), plasma structure, phase-space manipulation, beamline design, and undulator technology, among others. This paper presents our best attempt to provide a comprehensive overview of the global community efforts towards plasma-based FEL research and development..
High Power Laser Science and Engineering
- Publication Date: Jan. 01, 1900
- Vol. 9, Issue 4, 04000e57 (2021)
ReLaX: the Helmholtz International Beamline for Extreme Fields high-intensity short-pulse laser driver for relativistic laser–matter interaction and strong-field science using the high energy density instrument at the European X-ray free electron laser facility
A. Laso Garcia, H. Höppner, A. Pelka, C. Bähtz, E. Brambrink, S. Di Dio Cafiso, J. Dreyer, S. Göde, M. Hassan, T. Kluge, J. Liu, M. Makita, D. Möller, M. Nakatsutsumi, T. R. Preston, G. Priebe, H.-P. Schlenvoigt, J.-P. Schwinkendorf, M. Šmíd, A.-M. Talposi, M. Toncian, U. Zastrau, U. Schramm, T. E. Cowan, and T. Toncian
High-energy and high-intensity lasers are essential for pushing the boundaries of science. Their development has allowed leaps forward in basic research areas, including laser–plasma interaction, high-energy density science, metrology, biology and medical technology. The Helmholtz International Beamline for Extreme FieHigh-energy and high-intensity lasers are essential for pushing the boundaries of science. Their development has allowed leaps forward in basic research areas, including laser–plasma interaction, high-energy density science, metrology, biology and medical technology. The Helmholtz International Beamline for Extreme Fields user consortium contributes and operates two high-peak-power optical lasers using the high energy density instrument at the European X-ray free electron laser (EuXFEL) facility. These lasers will be used to generate transient extreme states of density and temperature to be probed by the X-ray beam. This paper introduces the ReLaX laser, a short-pulse high-intensity Ti:Sa laser system, and discusses its characteristics as available for user experiments. It will also present the first experimental commissioning results validating its successful integration into the EuXFEL infrastructure and viability as a relativistic-intensity laser driver..
High Power Laser Science and Engineering
- Publication Date: Jan. 01, 1900
- Vol. 9, Issue 4, 04000e59 (2021)
The seed laser system of the FERMI free-electron laser: design, performance and near future upgrades
P. Cinquegrana, A. Demidovich, G. Kurdi, I. Nikolov, P. Sigalotti, P. Susnjar, and M. B. Danailov
An important trend in extreme ultraviolet and soft X-ray free-electron laser (FEL) development in recent years has been the use of seeding by an external laser, aimed to improve the coherence and stability of the generated pulses. The high-gain harmonic generation seeding technique was first implemented at FERMI and prAn important trend in extreme ultraviolet and soft X-ray free-electron laser (FEL) development in recent years has been the use of seeding by an external laser, aimed to improve the coherence and stability of the generated pulses. The high-gain harmonic generation seeding technique was first implemented at FERMI and provided FEL radiation with high coherence as well as intensity and wavelength stability comparable to table-top ultrafast lasers. At FERMI, the seed laser has another very important function: it is the source of external laser pulses used in pump–probe experiments allowing one to achieve a record-low timing jitter. This paper describes the design, performance and operational modes of the FERMI seed laser in both single- and double-cascade schemes. In addition, the planned upgrade of the system to meet the challenges of the upgrade to echo-enabled harmonic generation mode is presented..
High Power Laser Science and Engineering
- Publication Date: Jan. 01, 1900
- Vol. 9, Issue 4, 04000e61 (2021)
Coherent optical vortex generation with multiple topological charges based on a seeded free electron laser
Hao Sun, Xiaofan Wang, Chao Feng, Lingjun Tu, Weijie Fan, and Bo Liu
To generate optical vortex with multiple topological charges, a simple scheme based on the phase mask shaping technique is proposed and applied in a seeded free electron laser. With a tailored phase mask, an extreme-ultraviolet (EUV) vortex with multiple topological charges can be produced. To prove the feasibility of To generate optical vortex with multiple topological charges, a simple scheme based on the phase mask shaping technique is proposed and applied in a seeded free electron laser. With a tailored phase mask, an extreme-ultraviolet (EUV) vortex with multiple topological charges can be produced. To prove the feasibility of this method, an eight-step phase mask is designed to shape the seed laser. The simulation results demonstrate that 100-MW, fully coherent EUV vortex pulses with topological charge 2 can be generated based on the proposed technique. We have also demonstrated the possibility of generating higher topological charges by using a phase mask with more steps..
High Power Laser Science and Engineering
- Publication Date: Jan. 01, 1900
- Vol. 9, Issue 4, 04000e65 (2021)
Compact and robust supercontinuum generation and post-compression using multiple thin plates
Xinhua Xie, Yunpei Deng, and Steven L. Johnson
We report on compact and robust supercontinuum generation and post-compression using transmission of light through multiple thin solid plates at the SwissFEL X-ray free-electron laser facility. A single stage consisting of three thin plates followed by a chirped mirror compressor achieves compression of initially 30-fsWe report on compact and robust supercontinuum generation and post-compression using transmission of light through multiple thin solid plates at the SwissFEL X-ray free-electron laser facility. A single stage consisting of three thin plates followed by a chirped mirror compressor achieves compression of initially 30-fs pulses with 800-nm center wavelength to sub-10-fs duration. We also demonstrate a two-stage implementation to compress the pulses further to sub-5-fs duration. With the two-stage setup, the generated supercontinuum includes wavelengths ranging from 500 to 1100 nm. The multi-plate setup is compact, robust, and stable, which makes it ideal for applications at free-electron laser facilities such as pump-probe experiments and laser-arrival timing tools..
High Power Laser Science and Engineering
- Publication Date: Jan. 01, 1900
- Vol. 9, Issue 4, 04000e66 (2021)
Research Articles
202 W dual-end-pumped Tm:YLF laser with a VBG as an output coupler
Disheng Wei, Shuyi Mi, Ke Yang, Junhui Li, Jinwen Tang, Baoquan Yao, Tongyu Dai, and Xiaoming Duan
We demonstrated a 202 W Tm:YLF slab laser using a reflecting volume Bragg grating (VBG) as an output coupler at room temperature. Two kinds of active heat dissipation methods were used for the VBG to suppress the shift of wavelength caused by its increasing temperature. The maximum continuous wave (CW) output power of We demonstrated a 202 W Tm:YLF slab laser using a reflecting volume Bragg grating (VBG) as an output coupler at room temperature. Two kinds of active heat dissipation methods were used for the VBG to suppress the shift of wavelength caused by its increasing temperature. The maximum continuous wave (CW) output power of 202 W using the microchannel cooling was obtained under the total incident pump power of 553 W, the corresponding slope efficiency and optical-to-optical conversion efficiency were 39.7% and 36.5%, respectively. The central wavelength was 1908.5 nm with the linewidth (full width at half maximum) of 0.57 nm. Meanwhile, with the laser output increasing from 30 to 202 W, the total shift was about 1.0 nm, and the wavelength was limited to two water absorption lines near 1908 nm. The beam quality factors M2 were measured to be 2.3 and 4.0 in x and y directions at 202 W..
High Power Laser Science and Engineering
- Publication Date: Jan. 01, 1900
- Vol. 9, Issue 4, 04000e48 (2021)
Recent progress of laboratory astrophysics with intense lasers
Hideaki Takabe, and Yasuhiro Kuramitsu
Thanks to a rapid progress of high-power lasers since the birth of laser by T. H. Maiman in 1960, intense lasers have been developed mainly for studying the scientific feasibility of laser fusion. Inertial confinement fusion with an intense laser has attracted attention as a new future energy source after two oil criseThanks to a rapid progress of high-power lasers since the birth of laser by T. H. Maiman in 1960, intense lasers have been developed mainly for studying the scientific feasibility of laser fusion. Inertial confinement fusion with an intense laser has attracted attention as a new future energy source after two oil crises in the 1970s and 1980s. From the beginning, the most challenging physics is known to be the hydrodynamic instability to realize the spherical implosion to achieve more than 1000 times the solid density. Many studies have been performed theoretically and experimentally on the hydrodynamic instability and resultant turbulent mixing of compressible fluids. During such activities in the laboratory, the explosion of supernova SN1987A was observed in the sky on 23 February 1987. The X-ray satellites have revealed that the hydrodynamic instability is a key issue to understand the physics of supernova explosion. After collaboration between laser plasma researchers and astrophysicists, the laboratory astrophysics with intense lasers was proposed and promoted around the end of the 1990s. The original subject was mainly related to hydrodynamic instabilities. However, after two decades of laboratory astrophysics research, we can now find a diversity of research topics. It has been demonstrated theoretically and experimentally that a variety of nonlinear physics of collisionless plasmas can be studied in laser ablation plasmas in the last decade. In the present paper, we shed light on the recent 10 topics studied intensively in laboratory experiments. A brief review is given by citing recent papers. Then, modeling cosmic-ray acceleration with lasers is reviewed in a following session as a special topic to be the future main topic in laboratory astrophysics research..
High Power Laser Science and Engineering
- Publication Date: Jan. 01, 1900
- Vol. 9, Issue 4, 04000e49 (2021)
Power-scalable sub-100-fs Tm laser at 2.08 μm
Li Wang, Weidong Chen, Yongguang Zhao, Hanlin Yang, Wei Jing, Zhongben Pan, Hui Huang, Jiachen Liu, Ji Eun Bae, Fabian Rotermund, Pavel Loiko, Xavier Mateos, Zhengping Wang, Xinguang Xu, Uwe Griebner, and Valentin Petrov
We report on a power-scalable sub-100-fs laser in the 2-μm spectral range using a Tm3+-doped ‘mixed’ (Lu,Sc)2O3 sesquioxide ceramic as an active medium. Pulses as short as 58 fs at 2076 nm with an average output power of 114 mW at a pulse repetition rate of approximately 82.9 MHz are generated by employing single-walleWe report on a power-scalable sub-100-fs laser in the 2-μm spectral range using a Tm3+-doped ‘mixed’ (Lu,Sc)2O3 sesquioxide ceramic as an active medium. Pulses as short as 58 fs at 2076 nm with an average output power of 114 mW at a pulse repetition rate of approximately 82.9 MHz are generated by employing single-walled carbon nanotubes as a saturable absorber. A higher average power of 350 mW at 2075 nm is obtained at the expense of the pulse duration (65 fs). A maximum average power of 486 mW is achieved for a pulse duration of 98 fs and an optical conversion efficiency of 22.3%, representing the highest value ever reported from sub-100-fs mode-locked Tm lasers..
High Power Laser Science and Engineering
- Publication Date: Jan. 01, 1900
- Vol. 9, Issue 4, 04000e50 (2021)
An evaluation of sustainability and societal impact of high-power laser and fusion technologies: a case for a new European research infrastructure
S. Atzeni, D. Batani, C. N. Danson, L. A. Gizzi, M. Perlado, M. Tatarakis, V. Tikhonchuk, and L. Volpe
Fusion energy research is delivering impressive new results emerging from different infrastructures and industrial devices evolving rapidly from ideas to proof-of-principle demonstration and aiming at the conceptual design of reactors for the production of electricity. A major milestone has recently been announced in lFusion energy research is delivering impressive new results emerging from different infrastructures and industrial devices evolving rapidly from ideas to proof-of-principle demonstration and aiming at the conceptual design of reactors for the production of electricity. A major milestone has recently been announced in laser fusion by the Lawrence Livermore National Laboratory and is giving new thrust to laser-fusion energy research worldwide. Here we discuss how these circumstances strongly suggest the need for a European intermediate-energy facility dedicated to the physics and technology of laser-fusion ignition, the physics of fusion materials and advanced technologies for high-repetition-rate, high-average-power broadband lasers. We believe that the participation of the broader scientific community and the increased engagement of industry, in partnership with research and academic institutions, make most timely the construction of this infrastructure of extreme scientific attractiveness..
High Power Laser Science and Engineering
- Publication Date: Jan. 01, 1900
- Vol. 9, Issue 4, 04000e52 (2021)
Use of KDP crystal as a Kerr nonlinear medium for compressing PW laser pulses down to 10 fs | Editors' Pick
Andrey Shaykin, Vladislav Ginzburg, Ivan Yakovlev, Anton Kochetkov, Alexey Kuzmin, Sergey Mironov, Ilya Shaikin, Sergey Stukachev, Vladimir Lozhkarev, Artem Prokhorov, and Efim Khazanov
The input pulse of the laser PEARL with energy of 18 J and pulse duration of about 60 fs was compressed to 10 fs after passage through a 4-mm-thick KDP crystal and reflection at two chirped mirrors with sum dispersion of -200 fs2. The experiments were performed for the В-integral values from 5 to 19 without visible damThe input pulse of the laser PEARL with energy of 18 J and pulse duration of about 60 fs was compressed to 10 fs after passage through a 4-mm-thick KDP crystal and reflection at two chirped mirrors with sum dispersion of -200 fs2. The experiments were performed for the В-integral values from 5 to 19 without visible damage to the optical elements, which indicates that small-scale self-focusing is not a significant issue. It was shown that, by virtue of the low dispersion of the group velocity, the KDP crystal has some advantages over silica: a larger pulse compression coefficient, especially at a small value of the В-integral (B = 5, …, 9), lower absolute values of chirped mirror dispersion, and also a possibility to control the magnitude of nonlinearity and dispersion by changing crystal orientation..
High Power Laser Science and Engineering
- Publication Date: Jan. 01, 1900
- Vol. 9, Issue 4, 04000e54 (2021)
Laser scaling for generation of megatesla magnetic fields by microtube implosions
D. Shokov, M. Murakami, and J. J. Honrubia
Microtube implosions are a novel scheme to generate ultrahigh magnetic fields of the megatesla order. These implosions are driven by ultraintense and ultrashort laser pulses. Using two- and three-dimensional particle simulations where megatesla-order magnetic fields can be achieved, we demonstrate scaling and criteria Microtube implosions are a novel scheme to generate ultrahigh magnetic fields of the megatesla order. These implosions are driven by ultraintense and ultrashort laser pulses. Using two- and three-dimensional particle simulations where megatesla-order magnetic fields can be achieved, we demonstrate scaling and criteria in terms of laser parameters, such as laser intensity and laser energy, to facilitate practical experiments toward the realization of extreme physical conditions, which have yet to be realized in laboratories. Microtube implosions should provide a new platform for studies in fundamental and applied physics relevant to ultrahigh magnetic fields..
High Power Laser Science and Engineering
- Publication Date: Jan. 01, 1900
- Vol. 9, Issue 4, 04000e56 (2021)
Observation and modelling of stimulated Raman scattering driven by an optically smoothed laser beam in experimental conditions relevant for shock ignition
G. Cristoforetti, S. Hüller, P. Koester, L. Antonelli, S. Atzeni, F. Baffigi, D. Batani, C. Baird, N. Booth, M. Galimberti, K. Glize, A. Héron, M. Khan, P. Loiseau, D. Mancelli, M. Notley, P. Oliveira, O. Renner, M. Smid, A. Schiavi, G. Tran, N. C. Woolsey, and L. A. Gizzi
We report results and modelling of an experiment performed at the Target Area West Vulcan laser facility, aimed at investigating laser–plasma interaction in conditions that are of interest for the shock ignition scheme in inertial confinement fusion (ICF), that is, laser intensity higher than ${10}^{16}$ $\mathrm{W}/{\We report results and modelling of an experiment performed at the Target Area West Vulcan laser facility, aimed at investigating laser–plasma interaction in conditions that are of interest for the shock ignition scheme in inertial confinement fusion (ICF), that is, laser intensity higher than ${10}^{16}$ $\mathrm{W}/{\mathrm{cm}}^2$ impinging on a hot ($T>1$ keV), inhomogeneous and long scalelength pre-formed plasma. Measurements show a significant stimulated Raman scattering (SRS) backscattering ($\sim 4\%{-}20\%$ of laser energy) driven at low plasma densities and no signatures of two-plasmon decay (TPD)/SRS driven at the quarter critical density region. Results are satisfactorily reproduced by an analytical model accounting for the convective SRS growth in independent laser speckles, in conditions where the reflectivity is dominated by the contribution from the most intense speckles, where SRS becomes saturated. Analytical and kinetic simulations well reproduce the onset of SRS at low plasma densities in a regime strongly affected by non-linear Landau damping and by filamentation of the most intense laser speckles. The absence of TPD/SRS at higher densities is explained by pump depletion and plasma smoothing driven by filamentation. The prevalence of laser coupling in the low-density profile justifies the low temperature measured for hot electrons ($7\!{-}\!12$ keV), which is well reproduced by numerical simulations..
High Power Laser Science and Engineering
- Publication Date: Jan. 01, 1900
- Vol. 9, Issue 4, 04000e60 (2021)
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