High-power laser pulses interacting with targets can generate intense electromagnetic pulses(EMPs),which can disrupt physical experimental diagnostics and even damage diagnostic equipment,posing a threat to the reliab...High-power laser pulses interacting with targets can generate intense electromagnetic pulses(EMPs),which can disrupt physical experimental diagnostics and even damage diagnostic equipment,posing a threat to the reliable operation of experiments.In this study,EMPs resulting from multi-petawatt laser irradiating nitrogen gas jets were systematically analyzed and investigated.The experimental results revealed that the EMP amplitude is positively correlated with the quantity and energy of the electrons captured and accelerated by the plasma channel.These factors are reflected by parameters such as laser energy and nitrogen gas jet pressure.Additionally,we propose several potential sources of EMPs produced by laser-irradiated gas jets and separately analyzed their spatiotemporal distributions.The findings provide insight into the mechanisms of EMP generation and introduce a new approach to achieve controllable EMPs by regulating the laser energy and gas jet pressure.展开更多
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 amplifie...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.展开更多
The problem of optimizing the parameters of a laser pulse compressor consisting of four identical diffraction gratings is solved analytically.The goal of optimization is to obtain maximum pulse power,completely exclud...The problem of optimizing the parameters of a laser pulse compressor consisting of four identical diffraction gratings is solved analytically.The goal of optimization is to obtain maximum pulse power,completely excluding both beam clipping on gratings and the appearance of spurious diffraction orders.The analysis is carried out in a general form for an out-of-plane compressor.Two particular‘plane'cases attractive from a practical point of view are analyzed in more detail:a standard Treacy compressor(TC)and a compressor with an angle of incidence equal to the Littrow angle(LC).It is shown that in both cases the LC is superior to the TC.Specifically,for 160-cm diffraction gratings,optimal LC design enables 107 PW for XCELS and 111 PW for SEL-100 PW,while optimal TC design enables 86 PW for both projects.展开更多
基金supported by the National Grand Instrument Project(No.2019YFF01014404)the Natural Science Foundation of China(Nos.12122501,61631001,11921006,U2241281,and 11975037)the Foundation of Science and Technology on Plasma Physics Laboratory(No.6142A04220108)。
文摘High-power laser pulses interacting with targets can generate intense electromagnetic pulses(EMPs),which can disrupt physical experimental diagnostics and even damage diagnostic equipment,posing a threat to the reliable operation of experiments.In this study,EMPs resulting from multi-petawatt laser irradiating nitrogen gas jets were systematically analyzed and investigated.The experimental results revealed that the EMP amplitude is positively correlated with the quantity and energy of the electrons captured and accelerated by the plasma channel.These factors are reflected by parameters such as laser energy and nitrogen gas jet pressure.Additionally,we propose several potential sources of EMPs produced by laser-irradiated gas jets and separately analyzed their spatiotemporal distributions.The findings provide insight into the mechanisms of EMP generation and introduce a new approach to achieve controllable EMPs by regulating the laser energy and gas jet pressure.
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.11304332,11704392,and 61705245)the Key Projects of International Cooperation in Chinese Academy of Sciences
文摘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.
基金supported by the Ministry of Science and Higher Education of the Russian Federation(075-15-2020906,Center of Excellence‘Center of Photonics’)。
文摘The problem of optimizing the parameters of a laser pulse compressor consisting of four identical diffraction gratings is solved analytically.The goal of optimization is to obtain maximum pulse power,completely excluding both beam clipping on gratings and the appearance of spurious diffraction orders.The analysis is carried out in a general form for an out-of-plane compressor.Two particular‘plane'cases attractive from a practical point of view are analyzed in more detail:a standard Treacy compressor(TC)and a compressor with an angle of incidence equal to the Littrow angle(LC).It is shown that in both cases the LC is superior to the TC.Specifically,for 160-cm diffraction gratings,optimal LC design enables 107 PW for XCELS and 111 PW for SEL-100 PW,while optimal TC design enables 86 PW for both projects.
