In the design and construction of ultra-high-peak-power laser systems,it is necessary to control the accumulated B-integral of the laser pulse,but currently there are no reasonable B-integral control standards for pic...In the design and construction of ultra-high-peak-power laser systems,it is necessary to control the accumulated B-integral of the laser pulse,but currently there are no reasonable B-integral control standards for picosecond and femtosecond lasers.We systematically evaluate the influence of the B-integral on the output capability of picosecond and femtosecond laser systems for the first time,to our knowledge,taking Nd:glass lasers and Ti:sapphire lasers as examples.For picosecond lasers,the temporal domain compressibility and the small-scale self-focusing effect restrict the B-integral to 1.7 and 1.9,respectively.For femtosecond lasers,the B-integral is mainly restricted by the small-scale self-focusing effect and the far-field focusability,which limit the B-integral to 1.5 and 1.7,respectively.The restriction made by far-field focusability can be largely relaxed by inserting a deformable mirror.The study of the factors restricting the B-integral will provide guidance for the design of ultra-high-peak-power laser systems.展开更多
We demonstrated a scheme of bandwidth expansion and pulse shape optimized to afford 10 PW laser design via spec-tral shaping,which uses the existing Nd:glass amplifier chain of the SG PW laser.Compared to the amplifie...We demonstrated a scheme of bandwidth expansion and pulse shape optimized to afford 10 PW laser design via spec-tral shaping,which uses the existing Nd:glass amplifier chain of the SG PW laser.Compared to the amplified pulse with a gain-narrowing effect,the required parameters of injected pulse energy,spectral bandwidth,and shape are analyzed,to-gether with their influence on the system B-integral,energy output capability,and temporal intensity contrast.A bandwidth expansion to 7 nm by using LiNbO_(3) birefringent spectral shaping resulted in an output energy of 2 kJ in a proof-of-principle experiment.The results are consistent with the theoretical prediction which suggests that the amplifier chain of SG PW laser is capable of achieving 6 kJ at the bandwidth of 7 nm and the B-integral<π.This will support a 10 PW laser with a compressed pulse energy of 4.8 kJ(efficiency=80%)at 480 fs.展开更多
A linearization model was used to analyze the laser beam propagation in a high power laser driver and the influence of the small-scale self-focusing and spatial phase noise on beam quality in disk amplifiers. The quan...A linearization model was used to analyze the laser beam propagation in a high power laser driver and the influence of the small-scale self-focusing and spatial phase noise on beam quality in disk amplifiers. The quantitative relations between intensities of spatial phase noise, B-integral, and beam intensity contrast in near field are given explicitly. A spectrum specification of phase noise has been obtained by setting a limit to the contrast of an output beam.展开更多
It was shown experimentally that for a 65-fs 17-J pulse,the effect of filamentation instability,also known as small-scale self-focusing,is much weaker than that predicted by stationary and nonstationary theoretical mo...It was shown experimentally that for a 65-fs 17-J pulse,the effect of filamentation instability,also known as small-scale self-focusing,is much weaker than that predicted by stationary and nonstationary theoretical models for high B-integral values.Although this discrepancy has been left unexplained at the moment,in practice no signs of filamentation may allow a breakthrough in nonlinear pulse post-compression at high laser energy.展开更多
Based on the paraxial wave equation,this study extends the theory of small-scale self-focusing(SSSF)from coherent beams to spatially partially coherent beams(PCBs)and derives a general theoretical equation that reveal...Based on the paraxial wave equation,this study extends the theory of small-scale self-focusing(SSSF)from coherent beams to spatially partially coherent beams(PCBs)and derives a general theoretical equation that reveals the underlying physics of the reduction in the B-integral of spatially PCBs.From the analysis of the simulations,the formula for the modulational instability(MI)gain coefficient of the SSSF of spatially PCBs is obtained by introducing a decrease factor into the formula of the MI gain coefficient of the SSSF of coherent beams.This decrease can be equated to a drop in the injected light intensity or an increase in the critical power.According to this formula,the reference value of the spatial coherence of spatially PCBs is given,offering guidance to overcome the output power limitation of the high-power laser driver due to SSSF.展开更多
基金supported by the National Key Laboratory of Plasma Physics Fund(Nos.6142A04220204 and6142A04230303)the Independent Research Project of the National Key Laboratory of Plasma Physics(Nos.JCKYS2023212802 and JCKYS2024212806)the National Key Research and Development Program of China(No.2022YFB3606305)。
文摘In the design and construction of ultra-high-peak-power laser systems,it is necessary to control the accumulated B-integral of the laser pulse,but currently there are no reasonable B-integral control standards for picosecond and femtosecond lasers.We systematically evaluate the influence of the B-integral on the output capability of picosecond and femtosecond laser systems for the first time,to our knowledge,taking Nd:glass lasers and Ti:sapphire lasers as examples.For picosecond lasers,the temporal domain compressibility and the small-scale self-focusing effect restrict the B-integral to 1.7 and 1.9,respectively.For femtosecond lasers,the B-integral is mainly restricted by the small-scale self-focusing effect and the far-field focusability,which limit the B-integral to 1.5 and 1.7,respectively.The restriction made by far-field focusability can be largely relaxed by inserting a deformable mirror.The study of the factors restricting the B-integral will provide guidance for the design of ultra-high-peak-power laser systems.
基金Projectsupported by the International Partnership Program of Chinese Academy of Sciences(Grant No.181231KYSB20170022)the Natural Science Foundation of Jiangsu Higher Education Institutions of China(Grant No.20KJB140020).
文摘We demonstrated a scheme of bandwidth expansion and pulse shape optimized to afford 10 PW laser design via spec-tral shaping,which uses the existing Nd:glass amplifier chain of the SG PW laser.Compared to the amplified pulse with a gain-narrowing effect,the required parameters of injected pulse energy,spectral bandwidth,and shape are analyzed,to-gether with their influence on the system B-integral,energy output capability,and temporal intensity contrast.A bandwidth expansion to 7 nm by using LiNbO_(3) birefringent spectral shaping resulted in an output energy of 2 kJ in a proof-of-principle experiment.The results are consistent with the theoretical prediction which suggests that the amplifier chain of SG PW laser is capable of achieving 6 kJ at the bandwidth of 7 nm and the B-integral<π.This will support a 10 PW laser with a compressed pulse energy of 4.8 kJ(efficiency=80%)at 480 fs.
基金This work is partially supported by the Key Project of the National Natural Science Foundation of China (Grant No. 69789801) the Team Project of Natural Science Foundation of Guangdong Province (Grant No. 20003061) the Funds of National Hi-Tech Committee
文摘A linearization model was used to analyze the laser beam propagation in a high power laser driver and the influence of the small-scale self-focusing and spatial phase noise on beam quality in disk amplifiers. The quantitative relations between intensities of spatial phase noise, B-integral, and beam intensity contrast in near field are given explicitly. A spectrum specification of phase noise has been obtained by setting a limit to the contrast of an output beam.
基金This work was supported by the Ministry of Science and Higher Education of the Russian Federation No.075-15-2020-906(Center of Excellence‘Center of Photonics’).
文摘It was shown experimentally that for a 65-fs 17-J pulse,the effect of filamentation instability,also known as small-scale self-focusing,is much weaker than that predicted by stationary and nonstationary theoretical models for high B-integral values.Although this discrepancy has been left unexplained at the moment,in practice no signs of filamentation may allow a breakthrough in nonlinear pulse post-compression at high laser energy.
文摘Based on the paraxial wave equation,this study extends the theory of small-scale self-focusing(SSSF)from coherent beams to spatially partially coherent beams(PCBs)and derives a general theoretical equation that reveals the underlying physics of the reduction in the B-integral of spatially PCBs.From the analysis of the simulations,the formula for the modulational instability(MI)gain coefficient of the SSSF of spatially PCBs is obtained by introducing a decrease factor into the formula of the MI gain coefficient of the SSSF of coherent beams.This decrease can be equated to a drop in the injected light intensity or an increase in the critical power.According to this formula,the reference value of the spatial coherence of spatially PCBs is given,offering guidance to overcome the output power limitation of the high-power laser driver due to SSSF.
