Journals >High Power Laser Science and Engineering
Contents
2017
Volume: 5 Issue 4
9 Article(s)
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FOCUS ON NATIONAL LABORATORY OF HIGH POWER LASER AND PHYSICS, SIOM
Improvements in long-term output energy performance of Nd:glass regenerative amplifiers
Peng Zhang, Youen Jiang, Jiangfeng Wang, Wei Fan, Xuechun Li, and Jianqiang Zhu
Optical damages, which severely degrade the output energy performance of Nd:glass regenerative amplifiers, are discussed in detail in this paper. By a series of experiments, it has been confirmed that these damages result from laser-induced contamination. Based on this work, several improvements are made to boost outpuOptical damages, which severely degrade the output energy performance of Nd:glass regenerative amplifiers, are discussed in detail in this paper. By a series of experiments, it has been confirmed that these damages result from laser-induced contamination. Based on this work, several improvements are made to boost output energy performance of the regenerative amplifier. The output energy of the regenerative amplifier after improvements declines 4% after 1000 h of operation, much less than it used to, 60% after 560 h of operation..
High Power Laser Science and Engineering
- Publication Date: Oct. 16, 2017
- Vol. 5, Issue 4, 04000e23 (2017)
Preparation of ultra-broadband antireflective coatings for amplifier blast shields by a sol–gel method
Huai Xiong, Bin Shen, Zhiya Chen, Xu Zhang, Haiyuan Li, Yongxing Tang, and Lili Hu
A type of $\unicode[STIX]{x1D706}/4$–$\unicode[STIX]{x1D706}/4$ ultra-broadband antireflective coating has been developed using modified low refractive silica and high refractive silica layers by a sol–gel dip coating method for amplifier blast shields of the Shen Guang II high power laser facility (SG-II facility). DeA type of $\unicode[STIX]{x1D706}/4$ –$\unicode[STIX]{x1D706}/4$ ultra-broadband antireflective coating has been developed using modified low refractive silica and high refractive silica layers by a sol–gel dip coating method for amplifier blast shields of the Shen Guang II high power laser facility (SG-II facility). Deposition of the first layer (high refractive index silica) involves baking at $200\,^{\circ }\text{C}$ in the post-treatment step. The second layer (low refractive index, $n=1.20$ ) uses low refractive index silica sol modified by acid catalysis. Thermal baking at temperatures no less than $500\,^{\circ }\text{C}$ for 60 min offers chemical stability, ethanol scratch resistance, and resistance to washing with water. The average residual reflection of dual-side-coated fused silica glass was less than 1% in the spectral range from 450 to 950 nm. Transmission gain has been evaluated by taking into account angular light, and the results show that the transmission gain increases with increasing light incidence. Even at $60^{\circ }$ , the transmission spectrum of the broadband antireflective coating effectively covered the main absorption peak of Nd:glass..
High Power Laser Science and Engineering
- Publication Date: Dec. 15, 2017
- Vol. 5, Issue 4, 04000e29 (2017)
HIGH INTENSITY LASER AND ATTOSECOND
302 W triple-frequency, single-mode, linearly polarized Yb-doped all-fiber amplifier
Xiang Zhao, Yifeng Yang, Hui Shen, Xiaolong Chen, Gang Bai, Jingpu Zhang, Yunfeng Qi, Bing He, and Jun Zhou
Stimulated Brillouin scattering (SBS) effect is currently the major limitation for the power scaling of single-frequency/narrow linewidth fiber laser systems. A single-mode linearly polarized all-fiber amplifier system is set up to investigate SBS effect in triple-frequency high-power amplifiers. With this amplifier, uStimulated Brillouin scattering (SBS) effect is currently the major limitation for the power scaling of single-frequency/narrow linewidth fiber laser systems. A single-mode linearly polarized all-fiber amplifier system is set up to investigate SBS effect in triple-frequency high-power amplifiers. With this amplifier, up to 302 W output power with 83% slope efficiency is achieved and the SBS threshold is scaled up to 12 dB. To the best of our knowledge, this is the highest output power of multifrequency laser from a single-mode polarization maintaining fiber. Good spectral properties and high brightness make this laser source available for the application of second harmonic generation, coherent beam combining..
High Power Laser Science and Engineering
- Publication Date: Dec. 15, 2017
- Vol. 5, Issue 4, 04000e31 (2017)
TARGET FABRICATION
REACH compliant epoxides used in the synthesis of Fe(III)-based aerogel monoliths for target fabrication
Alberto Valls Arrufat, Magdalena Budziszewska, Clement Lopez, Aymeric Nguyen, Jakub Sitek, Paul Jones, Chris Shaw, Ian Hayes, Gareth Cairns, and Glenn Leighton
Aerogel materials manufactured from metal oxides have been used as components in numerous high-energy density physics targets. These aerogels have been identified to be used as a future target material in the AWE fielded campaigns at the US National Ignition Facility. A wide variety of metal oxide aerogels are requiredAerogel materials manufactured from metal oxides have been used as components in numerous high-energy density physics targets. These aerogels have been identified to be used as a future target material in the AWE fielded campaigns at the US National Ignition Facility. A wide variety of metal oxide aerogels are required for future campaigns and therefore a versatile manufacturing route is sought; as such, an epoxide-assisted sol–gel route was investigated. Under the European Union Registration, Evaluation, Authorization and Restriction of Chemicals legislation, the most commonly used epoxide, propylene oxide, is recognized as a substance of very high concern (SVHC). This work sought to investigate suitable alternative epoxides for use in target manufacture. The outcome was the identification of synthesis routes for stable metal oxide aerogel monoliths using epoxides not subject to the above restrictions..
High Power Laser Science and Engineering
- Publication Date: Oct. 12, 2017
- Vol. 5, Issue 4, 04000e24 (2017)
Assembly and metrology of NIF target subassemblies using robotic systems | On the Cover
K.-J. Boehm, N. Alexander, J. Anderson, L. Carlson, and M. Farrell
With European Laser Facilities such as the Extreme Light Infrastructure (ELI) and the Helmholtz International Beamline for Extreme Fields (HIBEF) scheduled to come online within the next couple of years, General Atomics, as a major supplier of targets and target components for the High Energy Density Physics community With European Laser Facilities such as the Extreme Light Infrastructure (ELI) and the Helmholtz International Beamline for Extreme Fields (HIBEF) scheduled to come online within the next couple of years, General Atomics, as a major supplier of targets and target components for the High Energy Density Physics community in the United States, is gearing up to meet their demand for large numbers of low cost targets. Using the production of a subassembly for the National Ignition Facility’s fusion targets as an example, we demonstrate that through automation of assembly tasks, the design of targets and their experimental setup can be fairly complex while keeping the assembly time and cost as a minimum. A six-axis Mitsubishi robot is used in combination with vision feedback and a force–torque sensor to assemble target subassemblies of different scales and designs with minimal change of tooling, allowing for design flexibility and short assembly setup times. Implementing automated measurement routines on a Nikon NEXIV microscope further reduces the effort required for target metrology, while electronic data collection and transfer complete a streamlined target production operation that can be adapted to a large variety of target designs..
High Power Laser Science and Engineering
- Publication Date: Oct. 24, 2017
- Vol. 5, Issue 4, 04000e25 (2017)
Modeling the mechanical properties of ultra-thin polymer films
Francisco Espinosa-Loza, Michael Stadermann, Chantel Aracne-Ruddle, Rebecca Casey, Philip Miller, and Russel Whitesides
A modeling method to extract the mechanical properties of ultra-thin films (10–100 nm thick) from experimental data generated by indentation of freestanding circular films using a spherical indenter is presented. The relationship between the mechanical properties of the film and experimental parameters including load, A modeling method to extract the mechanical properties of ultra-thin films (10–100 nm thick) from experimental data generated by indentation of freestanding circular films using a spherical indenter is presented. The relationship between the mechanical properties of the film and experimental parameters including load, and deflection are discussed in the context of a constitutive material model, test variables, and analytical approaches. Elastic and plastic regimes are identified by comparison of finite element simulation and experimental data..
High Power Laser Science and Engineering
- Publication Date: Nov. 16, 2017
- Vol. 5, Issue 4, 04000e27 (2017)
X-ray computed tomography of adhesive wicking into carbon foam
Sav Chima
Laser target components consist of multicomponent porous and nonporous materials that are adhesively bonded together. In order to assess the extent and quantity of adhesive wicking into porous foam, micro X-ray computed tomography (CT) and image processing software have been utilized. Two different laser target configuLaser target components consist of multicomponent porous and nonporous materials that are adhesively bonded together. In order to assess the extent and quantity of adhesive wicking into porous foam, micro X-ray computed tomography (CT) and image processing software have been utilized. Two different laser target configurations have been assessed in situ and volume rendered images of the distribution and quantities of adhesive have been determined for each..
High Power Laser Science and Engineering
- Publication Date: Nov. 23, 2017
- Vol. 5, Issue 4, 04000e28 (2017)
ULTRAFAST OPTICS
Nonperturbative generation of above-threshold harmonics from pre-excited argon atoms in intense mid-infrared laser fields
Guihua Li, Hongqiang Xie, Ziting Li, Jinping Yao, Wei Chu, and Ya Cheng
We experimentally investigate the generation of above-threshold harmonics completely from argon atoms on an excited state using mid-infrared femtosecond laser pulses. The highly nonlinear dependences of the observed signal on the pulse energy and polarization of the probe laser pulses indicate its nonperturbative charaWe experimentally investigate the generation of above-threshold harmonics completely from argon atoms on an excited state using mid-infrared femtosecond laser pulses. The highly nonlinear dependences of the observed signal on the pulse energy and polarization of the probe laser pulses indicate its nonperturbative characteristic..
High Power Laser Science and Engineering
- Publication Date: Nov. 07, 2017
- Vol. 5, Issue 4, 04000e26 (2017)
Research Articles
kW-level, narrow-linewidth linearly polarized fiber laser with excellent beam quality through compact one-stage amplification scheme
Man Jiang, Pengfei Ma, Long Huang, Jiangming Xu, Pu Zhou, and Xijia Gu
In this manuscript, we demonstrate high-power, narrow-linewidth linearly polarized fiber laser with excellent beam quality through compact one-stage amplification scheme. By employing a single-mode–multimode–single-mode structure seed laser, a linearly polarized Yb-doped fiber laser with narrow linewidth and high outpuIn this manuscript, we demonstrate high-power, narrow-linewidth linearly polarized fiber laser with excellent beam quality through compact one-stage amplification scheme. By employing a single-mode–multimode–single-mode structure seed laser, a linearly polarized Yb-doped fiber laser with narrow linewidth and high output power is achieved. This laser, when used as a master oscillator, can be capable of suppressing the ASE in the process of power amplification. Thus, only one-stage amplification structure is used to scale up the laser power, and linearly polarized output with a polarization extinction ration of 14 dB, a narrow linewidth of 0.3 nm and an output power of 1018 W are achieved. Moreover, due to the good beam quality of seed laser and the well-designed amplifier stage, the beam quality of the output laser is near-diffraction-limited with $M_{x}^{2}\sim 1.18$ and $M_{y}^{2}\sim 1.24$ at the maximum power, and without mode instability occurring..
High Power Laser Science and Engineering
- Publication Date: Dec. 12, 2017
- Vol. 5, Issue 4, 04000e30 (2017)
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