The use of low-coherence light is expected to be one of the effective ways to suppress or even eliminate the laser–plasma instabilities that arise in attempts to achieve inertial confinement fusion.In this paper,a re...The use of low-coherence light is expected to be one of the effective ways to suppress or even eliminate the laser–plasma instabilities that arise in attempts to achieve inertial confinement fusion.In this paper,a review of low-coherence high-power laser drivers and related key techniques is first presented.Work at typical low-coherence laser facilities,including Gekko XII,PHEBUS,Pharos III,and Kanal-2 is described.The many key techniques that are used in the research and development of low-coherence laser drivers are described and analyzed,including low-coherence source generation,amplification,harmonic conversion,and beam smoothing of low-coherence light.Then,recent progress achieved by our group in research on a broadband low-coherence laser driver is presented.During the development of our low-coherence high-power laser facility,we have proposed and implemented many key techniques for working with low-coherence light,including source generation,efficient amplification and propagation,harmonic conversion,beam smoothing,and precise beam control.Based on a series of technological breakthroughs,a kilojoule low-coherence laser driver named Kunwu with a coherence time of only 300 fs has been built,and the first round of physical experiments has been completed.This high-power laser facility provides not only a demonstration and verification platform for key techniques and system integration of a low-coherence laser driver,but also a new type of experimental platform for research into,for example,high-energy-density physics and,in particular,laser–plasma interactions.展开更多
The achievement of ignition at the National Ignition Facility(NIF)has prompted a global wave of further research on inertial fusion energy(IFE).However,IFE requires a target gain G of 30-100,and it is hard to achieve ...The achievement of ignition at the National Ignition Facility(NIF)has prompted a global wave of further research on inertial fusion energy(IFE).However,IFE requires a target gain G of 30-100,and it is hard to achieve fusion at such high gain with the energy,configuration,and technical approach of the NIF.Here,we present a conceptual design for a next-generation laser driver that is applicable to multiple laser fusion schemes and provides 10 MJ,2-3 PW at 3ω(or 2ω,in which case the energy and power can be higher),and one shot per 30 min,with the aim of achieving G>30.It is also efficient,compact,and low in cost,and it has low susceptibility to laser-plasma instabilities.展开更多
Broadband frequency-tripling pulses with high energy are attractive for scientific research,such as inertial confinement fusion,but are difficult to scale up.Third-harmonic generation via nonlinear frequency conversio...Broadband frequency-tripling pulses with high energy are attractive for scientific research,such as inertial confinement fusion,but are difficult to scale up.Third-harmonic generation via nonlinear frequency conversion,however,remains a trade-off between bandwidth and conversion efficiency.Based on gradient deuterium deuterated potassium dihydrogen phosphate(KD_(x)H_(2-x)PO_(4),DKDP)crystal,here we report the generation of frequency-tripling pulses by rapid adiabatic passage with a low-coherence laser driver facility.The efficiency dependence on the phase-matching angle in a Type-II configuration is studied.We attained an output at 352 nm with a bandwidth of 4.4 THz and an efficiency of 36%.These results,to the best of our knowledge,represent the first experimental demonstration of gradient deuterium DKDP crystal in obtaining frequency-tripling pulses.Our research paves a new way for developing high-efficiency,large-bandwidth frequency-tripling technology.展开更多
We present a spatiotemporal model of pulse amplification in the double-pass active mirror(AM)geometry.Three types of overlap condition are studied,and the spatiotemporal scaling under the four-pulse overlapping(4 PO)c...We present a spatiotemporal model of pulse amplification in the double-pass active mirror(AM)geometry.Three types of overlap condition are studied,and the spatiotemporal scaling under the four-pulse overlapping(4 PO)condition is fully characterized for the first time,by mapping the temporal and spatial segments of beam to the instantaneous gain windows.Furthermore,the influence of spatiotemporal overlaps on the amplified energy,pulse distortion and intensity profile is unraveled for both AM and zigzag configurations.The model,verified by excellent agreement between the predicted and measured results,can be a powerful tool for designing and optimizing high energy multi-pass solid-state laser amplifiers with AM,zigzag and other geometries.展开更多
The damage characteristics of fused silica were investigated under low-temporal coherence light(LTCL).It was found that the laser-induced damage threshold(LIDT)of fused silica for the LTCL was lower than that of the s...The damage characteristics of fused silica were investigated under low-temporal coherence light(LTCL).It was found that the laser-induced damage threshold(LIDT)of fused silica for the LTCL was lower than that of the single longitudinal mode pulse laser,and for the LTCLs,the LIDTs decrease with the increasing of laser bandwidth,which is not consistent with the temporal spike intensity.This is due to the nonlinear self-focusing effect and multi-pulse accumulation effect.The specific reasons were analyzed based on theoretical simulation and experimental study.This research work is helpful and of great significance for the construction of high-power LTCL devices.展开更多
文摘The use of low-coherence light is expected to be one of the effective ways to suppress or even eliminate the laser–plasma instabilities that arise in attempts to achieve inertial confinement fusion.In this paper,a review of low-coherence high-power laser drivers and related key techniques is first presented.Work at typical low-coherence laser facilities,including Gekko XII,PHEBUS,Pharos III,and Kanal-2 is described.The many key techniques that are used in the research and development of low-coherence laser drivers are described and analyzed,including low-coherence source generation,amplification,harmonic conversion,and beam smoothing of low-coherence light.Then,recent progress achieved by our group in research on a broadband low-coherence laser driver is presented.During the development of our low-coherence high-power laser facility,we have proposed and implemented many key techniques for working with low-coherence light,including source generation,efficient amplification and propagation,harmonic conversion,beam smoothing,and precise beam control.Based on a series of technological breakthroughs,a kilojoule low-coherence laser driver named Kunwu with a coherence time of only 300 fs has been built,and the first round of physical experiments has been completed.This high-power laser facility provides not only a demonstration and verification platform for key techniques and system integration of a low-coherence laser driver,but also a new type of experimental platform for research into,for example,high-energy-density physics and,in particular,laser–plasma interactions.
基金supported by the National Natural Science Foundation of China(Grant No.12035002).
文摘The achievement of ignition at the National Ignition Facility(NIF)has prompted a global wave of further research on inertial fusion energy(IFE).However,IFE requires a target gain G of 30-100,and it is hard to achieve fusion at such high gain with the energy,configuration,and technical approach of the NIF.Here,we present a conceptual design for a next-generation laser driver that is applicable to multiple laser fusion schemes and provides 10 MJ,2-3 PW at 3ω(or 2ω,in which case the energy and power can be higher),and one shot per 30 min,with the aim of achieving G>30.It is also efficient,compact,and low in cost,and it has low susceptibility to laser-plasma instabilities.
基金supported by the President Funding Independent Project of the China Academy of Engineering Physics(No.YZJJZL2024200)the National Natural Science Foundation of China(No.62405298)the National Key Research and Development Program of China(No.2023YFA1608503).
文摘Broadband frequency-tripling pulses with high energy are attractive for scientific research,such as inertial confinement fusion,but are difficult to scale up.Third-harmonic generation via nonlinear frequency conversion,however,remains a trade-off between bandwidth and conversion efficiency.Based on gradient deuterium deuterated potassium dihydrogen phosphate(KD_(x)H_(2-x)PO_(4),DKDP)crystal,here we report the generation of frequency-tripling pulses by rapid adiabatic passage with a low-coherence laser driver facility.The efficiency dependence on the phase-matching angle in a Type-II configuration is studied.We attained an output at 352 nm with a bandwidth of 4.4 THz and an efficiency of 36%.These results,to the best of our knowledge,represent the first experimental demonstration of gradient deuterium DKDP crystal in obtaining frequency-tripling pulses.Our research paves a new way for developing high-efficiency,large-bandwidth frequency-tripling technology.
基金National Key Research and Development Program of China(No.2017YFB0405100)National Natural Science Foundation of China(No.61975087)Beijing Young Talents Support Project(No.2017000020124G044)。
文摘We present a spatiotemporal model of pulse amplification in the double-pass active mirror(AM)geometry.Three types of overlap condition are studied,and the spatiotemporal scaling under the four-pulse overlapping(4 PO)condition is fully characterized for the first time,by mapping the temporal and spatial segments of beam to the instantaneous gain windows.Furthermore,the influence of spatiotemporal overlaps on the amplified energy,pulse distortion and intensity profile is unraveled for both AM and zigzag configurations.The model,verified by excellent agreement between the predicted and measured results,can be a powerful tool for designing and optimizing high energy multi-pass solid-state laser amplifiers with AM,zigzag and other geometries.
基金supported by National Natural Science Foundation of China(No.12074353)。
文摘The damage characteristics of fused silica were investigated under low-temporal coherence light(LTCL).It was found that the laser-induced damage threshold(LIDT)of fused silica for the LTCL was lower than that of the single longitudinal mode pulse laser,and for the LTCLs,the LIDTs decrease with the increasing of laser bandwidth,which is not consistent with the temporal spike intensity.This is due to the nonlinear self-focusing effect and multi-pulse accumulation effect.The specific reasons were analyzed based on theoretical simulation and experimental study.This research work is helpful and of great significance for the construction of high-power LTCL devices.
