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Evolution of low-frequency noise passing through a spatial filter in a high power laser system

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Science China(Physics,Mechanics & Astronomy) 2011年第3期54卷 411-415页

作者： SUN PingPing LIU DeAn ZHANG YanLi LI XiaoYan ZHANG Yan zhu jianqiang National Laboratory on High Power Laser and Physics Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences Shanghai 201800 China

The theoretical model of spatial noise passing through a spatial filter is established in high power laser system under the small signal approximation. The transmission characteristic for a noise signal passing through spatial filters with different magnifications is analyzed by numerical simulation, according to the actual structure of the high power laser system. The results show that the spatial modulation period of low-frequency noise getting through the pinhole will be proportional to the magnification of the spatial filter. When the magnification is less than 1, the safe low-frequency noise will be extruded into the high-frequency region, which is the fast increasing part, and finally develops into the most dangerous part which can damage the optical devices. The conclusion of this research improves the relay imaging theory of a spatial filter and provides an important theoretical basis for a general design of high power laser systems.

关键词： high power laser spatial filter spatial modulation frequency modulation contrast ratio

Low-dose exposure to graphene oxide significantly increases the metal toxicity to macrophages by altering their cellular priming state

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Nano Research 2018年第8期11卷 4111-4122页

作者： jianqiang zhu Ming Xu Fanfan Wang Ming Gao Zhihong Zhang Yong Xu Wei Chen Sijin Liu State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental Sciences ChineseAcademy of Sciences Beijing 100085 China Department of Urology The Second Hospital of Tianjin Medical University Tianjin Institute of Urology Tianjin 30021 I China University of Chinese Academy of Sciences Beijing 100049 China College of Environmental Science and Engineering Tianjin Key Laboratory of Environmental Remediation and Pollution ControlNankai University Tianjin 300350 China jianqiang zhu and Ming Xu contributed equally to this work.

Owing to the novel physicochemical properties of graphene, materials such as graphene oxide （GO） are being developed for applications in various fields such as biomedicine. Nonetheless, considerable knowledge gaps still exist regarding the impact of GOs on environmental health and safety （EHS）. Thus far, its secondary toxicity, synergistic effects, and mal-adaption have not been focused much upon. Here, we show that at low concentrations （that did not directly result in significant cytotoxicity）, GO could greatly enhance metal toxicity in macrophages by altering their cellular priming state. Specificall）~ GO caused impairments to the cellular morphology and membrane integrity of macrophages, and remarkably enhanced the cellular uptake of Cd and other non-essential metal ions （such as Hg and Gd）. Furthermore, upon low-dose GO pre-treatment, the uptake of Cd at a non-toxic concentration brought about a remarkable amount of oxidative stress in macrophages, and ultimately resulted in increased cell death. Mechanistic investigations illustrated that GO pre-treatment triggered cell death through apoptosis because of Cd exposure. Overall this study＇s results reveal a new path for understanding the impact of GOs on EHS through the perspective of its synergistic and secondary effects, previously unidentified mechanisms via which nanomaterials might pose detrimental effects on organisms.

关键词： graphene oxide low-dose exposure cellular priming state synergistic effects metal toxicity

Improvements in long-term output energy performance of Nd:glass regenerative amplifiers

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High Power Laser Science and Engineering 2017年第4期5卷 1-7页

作者： Peng Zhang Youen Jiang Jiangfeng Wang Wei Fan Xuechun Li jianqiang zhu National Laboratory on High Power Laser and Physics Shanghai Institute of Optics and Fine MechanicsChinese Academy of SciencesShanghai 201800China

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 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.

关键词： diode-pumped solid-state laser and application high-power laser high-power laser related laser components laser amplifiers laser induced damage preamplifiers

Beam guiding system geometric arrangement in the target area of high-power laser drivers

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High Power Laser Science and Engineering 2015年第1期3卷 100-109页

作者： Lei Ren Dongfeng Zhao jianqiang zhu National Laboratory on High Power Laser and Physics Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Science

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.

关键词： beam guiding system laser drivers spherical hohlraum target areas

Analysis and construction status of SG-Ⅱ 5PW laser facility

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High Power Laser Science and Engineering 2018年第2期6卷 110-122页

作者： jianqiang zhu Xinglong Xie Meizhi Sun Jun Kang Qingwei Yang Ailin Guo Haidong zhu Ping zhu Qi Gao Xiao Liang Ziruo Cui Shunhua Yang Cheng Zhang Zunqi Lin National Laboratory on High Power Laser and Physics Shanghai 201800China Shanghai Institute of Optics and Fine Mechanics Chinese Academy of SciencesShanghai 201800China University of Chinese Academy of Sciences Beijing 100049China

We present a recent progress of the SG-II 5 PW facility, which designed a multi-petawatt ultrashort pulse laser based on optical parametric chirped-pulse amplification(OPCPA). The prior two optical parametric amplifiers have been accomplished and chirped pulses with an energy of 49.7 J and a full-width-at-half-maximum(FWHM) spectrum bandwidth of 85 nm have been achieved. In the PW-scale optical parametric amplification(OPA), with the pump pulse that has an energy of 118 J from the second harmonic generation of the SG-II 7 th beam, the pump-to-signal conversion efficiency is up to 41.9%, which to the best of our knowledge is the highest among all of the reported values for OPCPA systems. The compressed pulse is higher than 37 J in 21 fs(1.76 PW), and the focal spot is ～10 μm after the closed-loop corrections by the adaptive optics. Limited by the repetition of the pump laser, the SG-II 5 PW facility operates one shot per hour. It has successfully been employed for high energy physics experiments.

关键词： conversion efficiency multi-petawatt optical parametric amplification proton acceleration ultrashort pulse

Experimental Study of Fluid Flow in Thin Slab Continuous Caster Mould with Water-Model

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International Journal of Minerals,Metallurgy and Materials 1999年第1期13卷 15-19页

作者： Yanping Bao jianqiang zhu Naiyuan Tian Baomei Xu(Metallurgy School, University of Science and Technology Beijing, Beijing 100083, China) Metallurgy School University of Science and Technology Beijing Beijing 100083 China

Model study is an efficient method for optimizing the siructure of the mould and the submerged entry nozzle (SEN). Based on the similarity criteria, a full-scale water model has been established in accordance with the mould of thin-slab caster of the CSP (Compact Strip Production) operation. The effects of SEN structure including outlet area, outflow angle, nozzle width, thick-ness and immersion depth have been studied under high speed casting by measuring the amplitude and the impetus of top waves. By the orthogonal experiment design, not only the influence of the faCtors was estimated, but also the optimum work condition was judged. The rules of the fluid flow phenomena were summarized. The principle for choosing a reasonable structure of SEN was discussed.

关键词： thin-slab casting mould submerged entry nozzle (SEN) water-model

Output temporal contrast simulation of a large aperture high power short pulse laser system

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High Power Laser Science and Engineering 2014年第4期2卷 86-92页

作者： Ping zhu Xinglong Xie Xiaoping Ouyang jianqiang zhu Joint Laboratory on High Power Laser and Physics Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences University of Chinese Academy of Sciences

The work presented in this paper is a study of output temporal contrast degradation by near-field quality deterioration,such as intensity modulation and wavefront deviation, in a large aperture high power short pulse laser system. A twostep focusing algorithm with a coordinate transform based on the Fresnel approximation in the space domain is used for simulating the output focused by an off-axis parabolic mirror. The temporal contrast degradation by intensity modulation and wavefront deviation is analyzed and the influence of the diameter on the temporal contrast degradation is *** simulation and assumption results based on the parameters of the Shen Guang-II laser system are compared with the online experimental temporal contrast data. The near-field quality deterioration might lead to temporal contrast degradation, hindering higher temporal contrast in large aperture high power short pulse laser systems.

关键词： fill factor of laser beam temporal contrast ultrafast optics wavefront deviation

Application of image processing based on multiple filters in an alignment system

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High Power Laser Science and Engineering 2014年第3期2卷 56-61页

作者： Peiying Zeng Baoqiang zhu De'an Liu jianqiang zhu National Laboratory on High Power Laser and Physics Shanghai Institute of Optics and Fine MechanicsChinese Academy of Sciences

Beam alignment depends on CCD real-time image analysis and *** order to improve the quality of the alignment,multiple filters are used in far-field and near-field image *** multiple filters are constituted of an average filter and a median filter in different connection sequences,so that they can deal with different kinds of *** reduce the effect of the unknown nonlinear relationship between motor running steps and deviation pixels,a feasible methodology is offered to improve this phenomenon and a fuzzy algorithm is applied to the motor feedback control *** of the fuzzy control it is not necessary to establish an accurate mathematical model,so the impact of the nonlinear relationship will be reduced.

关键词： alignment fuzzy control image processing multiple filters

Development of a New Subermerged Entry Nozzle in Thin Slab Caster

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International Journal of Minerals,Metallurgy and Materials 1999年第3期13卷 183-186页

作者： Yanping Bao jianqiang zhu Wei Jiang Naiyuan Tian Baomei Xu(Metallurgy School, University of Science & Technology Beijing, Beijing 100083, China) Metallurgy School University of Science and Technology Beijing Beijing 100083 China

The fluid flow in the mould of the thin slab continuous caster has a large intluence on the quality of slabs and its *** fluid flow pattern can be controlled by the SEN (Submerged Entry Nozzle) structure. Traditional SEN can not decrease the surface turbulence and penetration depth at the same time, especially at high casting speed. In order to improve the fluid flow in the mould, a new structure SEN-Dissipation SEN have been invented. The water modeling experiments proved that the dissipation SEN could satisfy, the needs of fluid flow condition in the mould at high casting speed.

关键词： thin slab caster mould dissipation submerged entry nozzle water-model