Pub Date : 2021-03-05DOI: 10.11884/HPLPB202133.210097
Feng Guo-ying, Zheng Shijie, Tan Jianchang, Wen Junlong, Liao Xiaowei, Guo Jinmiao, Li Wei, Han Jing-Hua, Zhang Shu-Lin, Cai Siao, Luo Yun, W. Jianjun
In fields of practical applications such as the optical fiber communications, optical fiber lasers, and optical fiber sensinIn fields of practical applications such as the optical fiber communication, the optical fiber laser, and the optical fiber sensing, it is necessary to focus on the mode problems in optical fibers. Mode division multiplexing is an effective method to improve the information capacity of optical communication. Interference between modes is the basic method for the most of optical fiber sensing. Mode controlling technique is one of the key technologies for beam quality control of high-power fiber lasers. Therefore, research on the theory of optical fiber modes, modes’ generation, modes’ conversion, and mode characterization technology are of great significance and practical application value. In this paper, we discuss the mode and beam quality of the optical fiber, analyze the methods of multiple modes’ generation and conversion, and summarize the mode characterization methods by means of incoherent, coherent and low-coherence measurement. Currently, the fiber mode characterization is a hot research topic. Among a variety of characterization methods, the spatial and spectral imaging method (S2) and the spatial and spectral double Fourier transform method (F2) have significant advantages. Without knowing the geometric parameters of the fiber in advance, we can obtain characteristics such as the mode field distribution, the mode power ratio, and the group time delay. Results indicate that the F2 method is better for characterizing mode field distributions of high-power fiber lasers.
{"title":"Progress on mode field distribution and characterization technology of the optical fiber laser","authors":"Feng Guo-ying, Zheng Shijie, Tan Jianchang, Wen Junlong, Liao Xiaowei, Guo Jinmiao, Li Wei, Han Jing-Hua, Zhang Shu-Lin, Cai Siao, Luo Yun, W. Jianjun","doi":"10.11884/HPLPB202133.210097","DOIUrl":"https://doi.org/10.11884/HPLPB202133.210097","url":null,"abstract":"In fields of practical applications such as the optical fiber communications, optical fiber lasers, and optical fiber sensinIn fields of practical applications such as the optical fiber communication, the optical fiber laser, and the optical fiber sensing, it is necessary to focus on the mode problems in optical fibers. Mode division multiplexing is an effective method to improve the information capacity of optical communication. Interference between modes is the basic method for the most of optical fiber sensing. Mode controlling technique is one of the key technologies for beam quality control of high-power fiber lasers. Therefore, research on the theory of optical fiber modes, modes’ generation, modes’ conversion, and mode characterization technology are of great significance and practical application value. In this paper, we discuss the mode and beam quality of the optical fiber, analyze the methods of multiple modes’ generation and conversion, and summarize the mode characterization methods by means of incoherent, coherent and low-coherence measurement. Currently, the fiber mode characterization is a hot research topic. Among a variety of characterization methods, the spatial and spectral imaging method (S2) and the spatial and spectral double Fourier transform method (F2) have significant advantages. Without knowing the geometric parameters of the fiber in advance, we can obtain characteristics such as the mode field distribution, the mode power ratio, and the group time delay. Results indicate that the F2 method is better for characterizing mode field distributions of high-power fiber lasers.","PeriodicalId":39871,"journal":{"name":"强激光与粒子束","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42541999","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-02-15DOI: 10.11884/HPLPB202133.200233
Nie Yong, Yan Eryan, Yang Hao, Huang Nuoci, Chen Zhiguo, Zheng Qianglin, Bao Xiangyang, Hu Haiying
The effect of plasma on the transmission properties of electromagnetic waves and its application have always been one of the key research directions of electromagnetic theory and technology and plasma physics. The enhancement effect of collisional plasma on electromagnetic waves is a classic subject of the interaction between electromagnetic waves and plasma. Based on the transmission characteristics of electromagnetic waves in medium, this paper takes plasma as a special medium, and carries out experimental, theoretical and simulation studies on the transmission characteristics of high power microwave (HPM) atmospheric plasma and a certain range of electromagnetic waves under certain experimental conditions. The study found that the plasma formed by the S-band HPM under a vacuum of 50 Pa has a great influence on the electromagnetic wave transmission characteristics of different frequencies, and the electromagnetic wave transmission signal enhancement effect occurs regularly within a certain frequency range. A series of transmission waveforms of continuous electromagnetic waves of different frequencies passing through the HPM plasma area were obtained, and the waveforms were normalized. At 32.4 GHz, the transmission coefficient of continuous electromagnetic waves passing through the plasma area with plasma is about twice as high as that through the area without plasma. A simulation model was established, and the transmission coefficient distribution curve in the range of 31.5−32.5 GHz was obtained. The electromagnetic wave passing through the plasma showed a transmission enhancement effect, and at some frequency points, there was a transmission enhancement of about 1.9 times. The research results provides important technical support for the application of plasma in stealth, emergency communications, and black barrier communications.
{"title":"Transmission enhancement effect of electromagnetic wave in non-uniform collisional plasma","authors":"Nie Yong, Yan Eryan, Yang Hao, Huang Nuoci, Chen Zhiguo, Zheng Qianglin, Bao Xiangyang, Hu Haiying","doi":"10.11884/HPLPB202133.200233","DOIUrl":"https://doi.org/10.11884/HPLPB202133.200233","url":null,"abstract":"The effect of plasma on the transmission properties of electromagnetic waves and its application have always been one of the key research directions of electromagnetic theory and technology and plasma physics. The enhancement effect of collisional plasma on electromagnetic waves is a classic subject of the interaction between electromagnetic waves and plasma. Based on the transmission characteristics of electromagnetic waves in medium, this paper takes plasma as a special medium, and carries out experimental, theoretical and simulation studies on the transmission characteristics of high power microwave (HPM) atmospheric plasma and a certain range of electromagnetic waves under certain experimental conditions. The study found that the plasma formed by the S-band HPM under a vacuum of 50 Pa has a great influence on the electromagnetic wave transmission characteristics of different frequencies, and the electromagnetic wave transmission signal enhancement effect occurs regularly within a certain frequency range. A series of transmission waveforms of continuous electromagnetic waves of different frequencies passing through the HPM plasma area were obtained, and the waveforms were normalized. At 32.4 GHz, the transmission coefficient of continuous electromagnetic waves passing through the plasma area with plasma is about twice as high as that through the area without plasma. A simulation model was established, and the transmission coefficient distribution curve in the range of 31.5−32.5 GHz was obtained. The electromagnetic wave passing through the plasma showed a transmission enhancement effect, and at some frequency points, there was a transmission enhancement of about 1.9 times. The research results provides important technical support for the application of plasma in stealth, emergency communications, and black barrier communications.","PeriodicalId":39871,"journal":{"name":"强激光与粒子束","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46820921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-02-01DOI: 10.11884/HPLPB202133.200251
Li Ya’nan, Liu Shishuo, Cai Jun
In order to meet the demand of high-power and wide-band signal sources for G-band vacuum electronic devices, the research on G-band third harmonic amplifier is carried out. The amplifier utilizes the third harmonic current in the nonlinear beam-wave interaction of E-band TWT, and realizes G-band electromagnetic wave amplification by cascading harmonic interaction section. The design scheme of high performance and practical G-band wide-band high-power source adopts folded waveguide slow wave structure with modified circular bends, and the G-band third harmonic amplifier is simulated and optimized by using the microwave tube simulator package (MTSS) software. The result shows that the device can obtain harmonic output power greater than 3.6 W in the range of 15 GHz, conversion gain＞33.3 dB, and electronic efficiency＞0.36%. Compared with other miniaturized Terahertz radiation sources in this band, it has superior performance in terms of output power and bandwidth, which provides a design basis for the subsequent research of G-band third harmonic amplifier.
{"title":"Design of high-power and wide-band G-band third harmonic amplifier","authors":"Li Ya’nan, Liu Shishuo, Cai Jun","doi":"10.11884/HPLPB202133.200251","DOIUrl":"https://doi.org/10.11884/HPLPB202133.200251","url":null,"abstract":"In order to meet the demand of high-power and wide-band signal sources for G-band vacuum electronic devices, the research on G-band third harmonic amplifier is carried out. The amplifier utilizes the third harmonic current in the nonlinear beam-wave interaction of E-band TWT, and realizes G-band electromagnetic wave amplification by cascading harmonic interaction section. The design scheme of high performance and practical G-band wide-band high-power source adopts folded waveguide slow wave structure with modified circular bends, and the G-band third harmonic amplifier is simulated and optimized by using the microwave tube simulator package (MTSS) software. The result shows that the device can obtain harmonic output power greater than 3.6 W in the range of 15 GHz, conversion gain＞33.3 dB, and electronic efficiency＞0.36%. Compared with other miniaturized Terahertz radiation sources in this band, it has superior performance in terms of output power and bandwidth, which provides a design basis for the subsequent research of G-band third harmonic amplifier.","PeriodicalId":39871,"journal":{"name":"强激光与粒子束","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44740034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-15DOI: 10.11884/HPLPB202133.200137
Liu Haifeng, Li. Qiong, Zhang Qi-li, Zhang Gongmu, Song Hong-zhou, Zhao Yan-Hong, Sun Bo, Song Hai-feng
Hydrogen is the most abundant element in nature and an important object of astrophysics and ICF research. This paper briefly presents an overview of the research progress in wide-range equation of state and especially comments assessment of the most recent shock compression experiments on Omega laser facility and the theoretical models. Based on the previous work, the wide-range equation of state of hydrogen is constructed by using the improved chemical free energy model, the first-principle numerical simulation results and the multi-parameter equation of state model, which is applicable in the temperature range of 20−108 K and the density range of 10−7−2000 g/cm3. Compared with experimental results, such as those of shock compression experiment, static high pressure isotherm experiment and sound velocity experiment, the newly-constructed wide-range equation of state for hydrogen has high confidence and provides high precision data for astrophysics, inertial confinement fusion, international thermonuclear experimental reactor and other engineering physics designs. The construction and validation method of the hydrogen wide-range equation of state can also be applied to its isotope deuterium. In comparison with current models published abroad, the deuterium wide-range equation of state constructed by this method is in better agreement with the experimental data of principal and secondary Hugoniot published in 2019. This paper also points out the temperature-density regimesthat need attention in future research.
{"title":"Progress on wide-range equation of state for hydrogen and deuterium","authors":"Liu Haifeng, Li. Qiong, Zhang Qi-li, Zhang Gongmu, Song Hong-zhou, Zhao Yan-Hong, Sun Bo, Song Hai-feng","doi":"10.11884/HPLPB202133.200137","DOIUrl":"https://doi.org/10.11884/HPLPB202133.200137","url":null,"abstract":"Hydrogen is the most abundant element in nature and an important object of astrophysics and ICF research. This paper briefly presents an overview of the research progress in wide-range equation of state and especially comments assessment of the most recent shock compression experiments on Omega laser facility and the theoretical models. Based on the previous work, the wide-range equation of state of hydrogen is constructed by using the improved chemical free energy model, the first-principle numerical simulation results and the multi-parameter equation of state model, which is applicable in the temperature range of 20−108 K and the density range of 10−7−2000 g/cm3. Compared with experimental results, such as those of shock compression experiment, static high pressure isotherm experiment and sound velocity experiment, the newly-constructed wide-range equation of state for hydrogen has high confidence and provides high precision data for astrophysics, inertial confinement fusion, international thermonuclear experimental reactor and other engineering physics designs. The construction and validation method of the hydrogen wide-range equation of state can also be applied to its isotope deuterium. In comparison with current models published abroad, the deuterium wide-range equation of state constructed by this method is in better agreement with the experimental data of principal and secondary Hugoniot published in 2019. This paper also points out the temperature-density regimesthat need attention in future research.","PeriodicalId":39871,"journal":{"name":"强激光与粒子束","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46993901","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-15DOI: 10.11884/HPLPB202133.200173
Wang Lifeng, Ye Wenhua, Chen Zhu, L. Yongsheng, Ding Yong-kun, Zhao Kaige, Zhang Jing, L. Zhiyuan, Yan Yunpeng, Wu Junfeng, Fang Zhengfeng, Xue Chuang, Liang Jiwei, Wang Shuai, Hang Xudeng, Miao Wen-yong, YU Yong-teng, Tu Shao-yong, Yin Chuansheng, Cao Zhu-rong, Deng Bo, Yang Jia-min, Jiang Shao－en, Dong Jiaqin, Fang Zhi-heng, Jia Guo, X. Zhiyong, Huang Xiu-guang, Fu Si-Zu, Guo Hongyu, L. Yingjun, Cheng Tao, Gao Zhen, F. Lili, Wang Baoshan, Wang Yinghua, Zeng Weixin, Lu Yan, Kuang Yuanyuan, Zhao Zhenchao, Chen Wei, Dai Zhensheng, Gu Jianfa, Ge Fengjun, Kang Dongguo, Z. Huasen, Qiao Xiu-mei, Li Meng, Liu Changli, Shen Hao, Xu Yan, Gao Yao-ming, L. Yuanyuan, Huang Xiaoyan, Xu Xiaowen, Zheng Wu-di, Zou Shiyang, Wang Min, Zhu Shao-ping, Zhang Weiyan, He Xian-tu
Laser fusion, likely the ultimate solution to the crisis of human energy, is highly valued by the international community and has always been the focus of international research. It turns out that the biggest scientific obstacle of laser fusion is the effective control of the high-energy-density nonlinear flows during implosions. The research of high-energy-density nonlinear flows covers many different fields, such as high-energy-density physics, plasma physics, fluid mechanics, computing science, strong impact physics, and high pressure atomic physics. Meanwhile, the capability of multi-material and multi-scale numerical simulations as well as large laser facility with high output power is also needed. As an emerging research field, it is full of all kinds of novel phenomena to be explored. In addition, hydrodynamic instabilities and the subsequent turbulent mixing in high-energy-density flows, are also important processes in astrophysical phenomena (e.g., galaxy collision and merging, stellar evolution, formation of protostars and supernova explosion) and involve with the core content of astrophysics. This paper reviews, firstly the status and progress, as well as the challenges and opportunities of high-energy-density nonlinear flows research. Secondly, it introduces hydrodynamic instabilities during implosions in central ignition laser fusion, among which, key factors related to the bottleneck of implosion performance of the National Ignition Facility (NIF) in the United States are condensed. Next, it summarizes the development of hydrodynamic instability experiments in laser fusion abroad. Finally, it lists some key achievements on the fundamental issues of hydrodynamic instabilities by the laser fusion implosion physics team in China over the last three years. This team has been engaged in the research and control of nonlinear flows in laser fusion implosions, as well as the research and design of target physics. A lot of improvements have been made in recent years on the theoretical analysis and numerical simulation of outstanding issues for hydrodynamic instabilities in laser fusion implosions, and the design and analysis of experiments on large lasers, which greatly promoted the development of this research direction in China.
{"title":"Review of hydrodynamic instabilities in inertial confinement fusion implosions","authors":"Wang Lifeng, Ye Wenhua, Chen Zhu, L. Yongsheng, Ding Yong-kun, Zhao Kaige, Zhang Jing, L. Zhiyuan, Yan Yunpeng, Wu Junfeng, Fang Zhengfeng, Xue Chuang, Liang Jiwei, Wang Shuai, Hang Xudeng, Miao Wen-yong, YU Yong-teng, Tu Shao-yong, Yin Chuansheng, Cao Zhu-rong, Deng Bo, Yang Jia-min, Jiang Shao－en, Dong Jiaqin, Fang Zhi-heng, Jia Guo, X. Zhiyong, Huang Xiu-guang, Fu Si-Zu, Guo Hongyu, L. Yingjun, Cheng Tao, Gao Zhen, F. Lili, Wang Baoshan, Wang Yinghua, Zeng Weixin, Lu Yan, Kuang Yuanyuan, Zhao Zhenchao, Chen Wei, Dai Zhensheng, Gu Jianfa, Ge Fengjun, Kang Dongguo, Z. Huasen, Qiao Xiu-mei, Li Meng, Liu Changli, Shen Hao, Xu Yan, Gao Yao-ming, L. Yuanyuan, Huang Xiaoyan, Xu Xiaowen, Zheng Wu-di, Zou Shiyang, Wang Min, Zhu Shao-ping, Zhang Weiyan, He Xian-tu","doi":"10.11884/HPLPB202133.200173","DOIUrl":"https://doi.org/10.11884/HPLPB202133.200173","url":null,"abstract":"Laser fusion, likely the ultimate solution to the crisis of human energy, is highly valued by the international community and has always been the focus of international research. It turns out that the biggest scientific obstacle of laser fusion is the effective control of the high-energy-density nonlinear flows during implosions. The research of high-energy-density nonlinear flows covers many different fields, such as high-energy-density physics, plasma physics, fluid mechanics, computing science, strong impact physics, and high pressure atomic physics. Meanwhile, the capability of multi-material and multi-scale numerical simulations as well as large laser facility with high output power is also needed. As an emerging research field, it is full of all kinds of novel phenomena to be explored. In addition, hydrodynamic instabilities and the subsequent turbulent mixing in high-energy-density flows, are also important processes in astrophysical phenomena (e.g., galaxy collision and merging, stellar evolution, formation of protostars and supernova explosion) and involve with the core content of astrophysics. This paper reviews, firstly the status and progress, as well as the challenges and opportunities of high-energy-density nonlinear flows research. Secondly, it introduces hydrodynamic instabilities during implosions in central ignition laser fusion, among which, key factors related to the bottleneck of implosion performance of the National Ignition Facility (NIF) in the United States are condensed. Next, it summarizes the development of hydrodynamic instability experiments in laser fusion abroad. Finally, it lists some key achievements on the fundamental issues of hydrodynamic instabilities by the laser fusion implosion physics team in China over the last three years. This team has been engaged in the research and control of nonlinear flows in laser fusion implosions, as well as the research and design of target physics. A lot of improvements have been made in recent years on the theoretical analysis and numerical simulation of outstanding issues for hydrodynamic instabilities in laser fusion implosions, and the design and analysis of experiments on large lasers, which greatly promoted the development of this research direction in China.","PeriodicalId":39871,"journal":{"name":"强激光与粒子束","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46789218","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-15DOI: 10.11884/HPLPB202133.200339
Ren Jie-Ru, Wang Jiale, Chen Benzheng, Xu Hao, Zhang Yanning, W. Wenqing, Xu Xing, Ma Bubo, Hu Zhongmin, Yinjie Shuai, Feng Jianhua, S. Shasha, Z. Shizheng, D. Hoffmann, Zhao Yong-tao
Intense ion beams can quasi-isometrically heat any high-density sample and generate warm dense matter (WDM) with large scale, uniform state distribution without any shock wave inside. This kind of driver provides a new opportunity for the laboratory high energy density physics (HEDP) research. The typical intense ion beam accelerators around the world, as well as their critical parameters and research plans of HEDP study are introduced.The progress of ion driven WDM generation and evolution using PIC and hydrodynamic simulations is shown. The high energy electron beam radiography technique with high spatial resolution, high temporal evolution, and high penetrating ability is also introduced. The collisional and charge transfer processes of the interaction between low-to-medium energy ion and plasma are analyzed. The nonlinear effect during the intense ion beam stopping and transportation process are presented.
{"title":"Progress of intense heavy ion beam driven high energy density physics","authors":"Ren Jie-Ru, Wang Jiale, Chen Benzheng, Xu Hao, Zhang Yanning, W. Wenqing, Xu Xing, Ma Bubo, Hu Zhongmin, Yinjie Shuai, Feng Jianhua, S. Shasha, Z. Shizheng, D. Hoffmann, Zhao Yong-tao","doi":"10.11884/HPLPB202133.200339","DOIUrl":"https://doi.org/10.11884/HPLPB202133.200339","url":null,"abstract":"Intense ion beams can quasi-isometrically heat any high-density sample and generate warm dense matter (WDM) with large scale, uniform state distribution without any shock wave inside. This kind of driver provides a new opportunity for the laboratory high energy density physics (HEDP) research. The typical intense ion beam accelerators around the world, as well as their critical parameters and research plans of HEDP study are introduced.The progress of ion driven WDM generation and evolution using PIC and hydrodynamic simulations is shown. The high energy electron beam radiography technique with high spatial resolution, high temporal evolution, and high penetrating ability is also introduced. The collisional and charge transfer processes of the interaction between low-to-medium energy ion and plasma are analyzed. The nonlinear effect during the intense ion beam stopping and transportation process are presented.","PeriodicalId":39871,"journal":{"name":"强激光与粒子束","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43524410","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-07DOI: 10.11884/HPLPB202133.200182
Liu Yu, Li Min, Huang Shan, Wu Wenjie, Feng Xi, Shen Benjian, Song Huaqing, Tao Rumao, W. Jianjun, Jing Feng
To realize of passive-cooling high power fiber cladding light stripper, it is important to optimize the thermal management of both the fiber and the package. By using Teflon capillaries to make segmental etching configuration on fiber, using copper as the package material, and optimizing the package structure through finite element thermal simulations, cladding light stripper capable of handling 500 W power was designed and fabricated. It was experimentally verified that the stripping efficiency reached 23.7 dB and the temperature increase rate on the bare fiber of cladding light stripper was as low as 0.007 ℃/W. In addition, at 540 W of power injection, cladding light stripper could work continuously if mounted on water-cooled cold plate, and could work for 50 s each time if mounted on cold plate filled with phase-change material, with the maximum temperature of package being 58.7 ℃ and 80 ℃ respectively. The researches and results could provide valuable information to the design and development of high power fiber lasers.
{"title":"＞500 W passively-cooled fiber cladding light stripper","authors":"Liu Yu, Li Min, Huang Shan, Wu Wenjie, Feng Xi, Shen Benjian, Song Huaqing, Tao Rumao, W. Jianjun, Jing Feng","doi":"10.11884/HPLPB202133.200182","DOIUrl":"https://doi.org/10.11884/HPLPB202133.200182","url":null,"abstract":"To realize of passive-cooling high power fiber cladding light stripper, it is important to optimize the thermal management of both the fiber and the package. By using Teflon capillaries to make segmental etching configuration on fiber, using copper as the package material, and optimizing the package structure through finite element thermal simulations, cladding light stripper capable of handling 500 W power was designed and fabricated. It was experimentally verified that the stripping efficiency reached 23.7 dB and the temperature increase rate on the bare fiber of cladding light stripper was as low as 0.007 ℃/W. In addition, at 540 W of power injection, cladding light stripper could work continuously if mounted on water-cooled cold plate, and could work for 50 s each time if mounted on cold plate filled with phase-change material, with the maximum temperature of package being 58.7 ℃ and 80 ℃ respectively. The researches and results could provide valuable information to the design and development of high power fiber lasers.","PeriodicalId":39871,"journal":{"name":"强激光与粒子束","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47236223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-07DOI: 10.11884/HPLPB202133.200197
Fan Peiliang, H. Xiaozhong, Yang Liu, W. Tao, Jiang Xiaoguo, Li Yiding, Zhang Xiaoding, Wang Ke, Yang Xinglin
In one high repetition frequency X-ray free electron laser (XFEL) equipment, the electron gun and compensate solenoid have special structure in the photoinjector, thus the electric field and the magnetic field overlaps near the cathode. The thermal emittance of the cathode should be measured in the experiment. The solenoid scan method used to measure the thermal emittance is not suitable for the overlapping field, because it works effectively only when the rms emittance keeps constant. As the normalized phase space can avoid the influence of the electric field, we tried to use the solenoid scan method in normalized phase space. Using simulation code to do simulations and analysis, we finally demonstrate that this method is feasible for measurement of thermal emittance of the photoinjector which has overlapping field.
{"title":"Simulation of the solenoid scan method used in overlapping field for thermal emittance measurement","authors":"Fan Peiliang, H. Xiaozhong, Yang Liu, W. Tao, Jiang Xiaoguo, Li Yiding, Zhang Xiaoding, Wang Ke, Yang Xinglin","doi":"10.11884/HPLPB202133.200197","DOIUrl":"https://doi.org/10.11884/HPLPB202133.200197","url":null,"abstract":"In one high repetition frequency X-ray free electron laser (XFEL) equipment, the electron gun and compensate solenoid have special structure in the photoinjector, thus the electric field and the magnetic field overlaps near the cathode. The thermal emittance of the cathode should be measured in the experiment. The solenoid scan method used to measure the thermal emittance is not suitable for the overlapping field, because it works effectively only when the rms emittance keeps constant. As the normalized phase space can avoid the influence of the electric field, we tried to use the solenoid scan method in normalized phase space. Using simulation code to do simulations and analysis, we finally demonstrate that this method is feasible for measurement of thermal emittance of the photoinjector which has overlapping field.","PeriodicalId":39871,"journal":{"name":"强激光与粒子束","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45379772","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-07DOI: 10.11884/HPLPB202133.200223
Rao Junfeng, Liu Encheng, Wang Yong-gang, Jiang Song, Li Zi
With the wide application of all-solid-state high-voltage pulse generators in the fields of material modification, biomedicine and industry, all-solid-state pulse generators are developing in the direction of miniaturization, intelligence and modularization. To further reduce the volume and cost of the power supply, this paper proposes a positive self-triggering all-solid-state Marx generator topology. It only needs to provide an isolated signal to control the turn-on and turn-off of discharging switch in the first stage, and the gates of the adjacent-stage discharging switches will be automatically charged and discharged through the inter-stage capacitors, so that they turn on and off one by one. This topology makes the driving circuit of the multiple switches in the Marx generators much simpler and does not need to provide a multi-channel driving power supply with isolated power supplies, and also avoids the dynamic and static voltage balancing problems of the switches. Based on this topology, a 17-stage positive polarity Marx generator prototype is built, and the voltage amplitudes and pulse widths are continuously adjustable. It outputs 10 kV positive high-voltage pulses at a repetition frequency of 100 Hz over a 10 kΩ resistive load. The leading edge is approximately 328 ns. The prototype is small in size and stable in work, which verifies the feasibility of this topology.
{"title":"Self-triggering all-solid-state Marx generator","authors":"Rao Junfeng, Liu Encheng, Wang Yong-gang, Jiang Song, Li Zi","doi":"10.11884/HPLPB202133.200223","DOIUrl":"https://doi.org/10.11884/HPLPB202133.200223","url":null,"abstract":"With the wide application of all-solid-state high-voltage pulse generators in the fields of material modification, biomedicine and industry, all-solid-state pulse generators are developing in the direction of miniaturization, intelligence and modularization. To further reduce the volume and cost of the power supply, this paper proposes a positive self-triggering all-solid-state Marx generator topology. It only needs to provide an isolated signal to control the turn-on and turn-off of discharging switch in the first stage, and the gates of the adjacent-stage discharging switches will be automatically charged and discharged through the inter-stage capacitors, so that they turn on and off one by one. This topology makes the driving circuit of the multiple switches in the Marx generators much simpler and does not need to provide a multi-channel driving power supply with isolated power supplies, and also avoids the dynamic and static voltage balancing problems of the switches. Based on this topology, a 17-stage positive polarity Marx generator prototype is built, and the voltage amplitudes and pulse widths are continuously adjustable. It outputs 10 kV positive high-voltage pulses at a repetition frequency of 100 Hz over a 10 kΩ resistive load. The leading edge is approximately 328 ns. The prototype is small in size and stable in work, which verifies the feasibility of this topology.","PeriodicalId":39871,"journal":{"name":"强激光与粒子束","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46275406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-07DOI: 10.11884/HPLPB202133.200241
Xie Pengfei, Lei Jun, Lu Wenqiang, Gao Songxin, Wang Zhao, Cao Liqiang, Wang Chengqian
To improve slow axis beam quality of diode laser (LD) and decrease slow axis divergence angle, a new package with lateral heat flow suppression was designed utilizing the difference in thermal conductivity between air and heat sink. The finite element analysis software was used to analyze the temperature distribution with lateral flow suppression package. It is shown that diode laser chip soldered on trough heat sink with width W=120 μm and length L=4000 μm can reduce slow axis divergence angle about 14%, from 12.25° to 10.49°, when working current was 15A. Correspondingly, beam parameter product (BPP) can reduce from 5.344 mm·mrad to 4.5763 mm·mrad and the brightness of slow axis increased about 5.5% than before. According to the result, the lateral flow suppression package can weaken higher order mode caused by thermal lens effect of diode laser so that decrease slow axis divergence angle effectively.
{"title":"Experimental investigation of the package of diode laser chip based on lateral heat flow suppression","authors":"Xie Pengfei, Lei Jun, Lu Wenqiang, Gao Songxin, Wang Zhao, Cao Liqiang, Wang Chengqian","doi":"10.11884/HPLPB202133.200241","DOIUrl":"https://doi.org/10.11884/HPLPB202133.200241","url":null,"abstract":"To improve slow axis beam quality of diode laser (LD) and decrease slow axis divergence angle, a new package with lateral heat flow suppression was designed utilizing the difference in thermal conductivity between air and heat sink. The finite element analysis software was used to analyze the temperature distribution with lateral flow suppression package. It is shown that diode laser chip soldered on trough heat sink with width W=120 μm and length L=4000 μm can reduce slow axis divergence angle about 14%, from 12.25° to 10.49°, when working current was 15A. Correspondingly, beam parameter product (BPP) can reduce from 5.344 mm·mrad to 4.5763 mm·mrad and the brightness of slow axis increased about 5.5% than before. According to the result, the lateral flow suppression package can weaken higher order mode caused by thermal lens effect of diode laser so that decrease slow axis divergence angle effectively.","PeriodicalId":39871,"journal":{"name":"强激光与粒子束","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47207988","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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