Journals >High Power Laser Science and Engineering
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1 Issue (s), 8 Article (s)
Vol. 13, Iss.2—Mar.1, 2025 • pp: e13- Spec. pp:
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Vol. 13, Iss.2-Mar..1,2025
Research Articles
Ultrafast characterization of plasma critical surface evolution in inertial confinement fusion experiments with chirped laser pulsesLinjun Li, Zhantao Lu, Xinglong Xie, Meizhi Sun, Xiao Liang, Qingwei Yang, Ailin Guo, Ping Zhu, Xuejie Zhang, Dongjun Zhang, Hao Xue, Guoli Zhang, Rashid Ul Haq, Haidong Zhu, Jun Kang, and Jianqiang Zhu
Laser-driven inertial confinement fusion (ICF) diagnostics play a crucial role in understanding the complex physical processes governing ICF and enabling ignition. During the ICF process, the interaction between the high-power laser and ablation material leads to the formation of a plasma critical surface, which reflects a significant portion of the driving laser, reducing the efficiency of laser energy conversion into implosive kinetic energy. Effective diagnostic methods for the critical surface remain elusive. In this work, we propose a novel optical diagnostic approach to investigate the plasma critical surface. This method has been experimentally validated, providing new insights into the critical surface morphology and dynamics. This advancement represents a significant step forward in ICF diagnostic capabilities, with the potential to inform strategies for enhancing the uniformity of the driving laser and target surface, ultimately improving the efficiency of converting laser energy into implosion kinetic energy and enabling ignition.Laser-driven inertial confinement fusion (ICF) diagnostics play a crucial role in understanding the complex physical processes governing ICF and enabling ignition. During the ICF process, the interaction between the high-power laser and ablation material leads to the formation of a plasma critical surface, which reflects a significant portion of the driving laser, reducing the efficiency of laser energy conversion into implosive kinetic energy. Effective diagnostic methods for the critical surface remain elusive. In this work, we propose a novel optical diagnostic approach to investigate the plasma critical surface. This method has been experimentally validated, providing new insights into the critical surface morphology and dynamics. This advancement represents a significant step forward in ICF diagnostic capabilities, with the potential to inform strategies for enhancing the uniformity of the driving laser and target surface, ultimately improving the efficiency of converting laser energy into implosion kinetic energy and enabling ignition.
High Power Laser Science and Engineering
- Publication Date: Jan. 10, 2025
- Vol. 13, Issue 2, 02000e13 (2025)
Research Articles
An investigation of the emittance of escaping fast electron beams from planar and nanowire targetsE. J. Hume, P. Köster, F. Baffigi, F. Brandi, D. Calestani, G. Cristoforetti, L. Fulgentini, L. Labate, A. Marasciulli, S. Morris, D. Palla, M. Salvadori, M. Villani, L. A. Gizzi, and K. L. Lancaster
Fast electron generation and transport in high-intensity laser–solid interactions induces X-ray emission and drives ion acceleration. Effective production of these sources hinges on an efficient laser absorption into the fast electron population and control of divergence as the beam propagates through the target. Nanowire targets can be employed to increase the laser absorption, but it is not yet clear how the fast electron beam properties are modified. Here we present novel measurements of the emittance of the exiting fast electron beam from irradiated solid planar and nanowire targets via a pepper-pot diagnostic. The measurements indicate a greater fast electron emittance is obtained from nanowire targets. Two-dimensional particle-in-cell simulations support this conclusion, revealing beam defocusing at the wire–substrate boundary, a higher fast electron temperature and transverse oscillatory motion around the wires.Fast electron generation and transport in high-intensity laser–solid interactions induces X-ray emission and drives ion acceleration. Effective production of these sources hinges on an efficient laser absorption into the fast electron population and control of divergence as the beam propagates through the target. Nanowire targets can be employed to increase the laser absorption, but it is not yet clear how the fast electron beam properties are modified. Here we present novel measurements of the emittance of the exiting fast electron beam from irradiated solid planar and nanowire targets via a pepper-pot diagnostic. The measurements indicate a greater fast electron emittance is obtained from nanowire targets. Two-dimensional particle-in-cell simulations support this conclusion, revealing beam defocusing at the wire–substrate boundary, a higher fast electron temperature and transverse oscillatory motion around the wires.
High Power Laser Science and Engineering
- Publication Date: Jan. 15, 2025
- Vol. 13, Issue 2, 02000e14 (2025)
Research Articles
High-fidelity delivery of kilowatt-level single-mode lasers through a tapered multimode fiber over one hundred metersXiao Chen, Shanmin Huang, Liangjin Huang, Zhiping Yan, Zhiyong Pan, Zongfu Jiang, and Pu Zhou
The immediate priorities for high-power delivery employing solid-core fibers are balancing the nonlinear effect and beam deterioration. Here, the scheme of tapered multimode fiber is experimentally realized. The tapered multimode fiber, featuring a 15 m (24/200 μm)–10 m (tapered region)–80 m (48/400 μm) profile, guides the laser with a weakly coupled condition. With the input power of 1035 W, the maximum output power over the 105 m delivery is 962 W, corresponding to a high efficiency of over 93% and a nonlinear suppression ratio of over 50 dB. Mode resolving results show high-order-mode contents of less than –30 dB in the whole delivery path, resulting in a high-fidelity delivery with M2 factors of 1.20 and 1.23 for the input and output lasers, respectively. Furthermore, the ultimate limits of delivery lengths for solid-core weakly coupled fibers are discussed. This work provides a valuable reference to reconsider the future boom of high-power laser delivery based on solid-core fibers.The immediate priorities for high-power delivery employing solid-core fibers are balancing the nonlinear effect and beam deterioration. Here, the scheme of tapered multimode fiber is experimentally realized. The tapered multimode fiber, featuring a 15 m (24/200 μm)–10 m (tapered region)–80 m (48/400 μm) profile, guides the laser with a weakly coupled condition. With the input power of 1035 W, the maximum output power over the 105 m delivery is 962 W, corresponding to a high efficiency of over 93% and a nonlinear suppression ratio of over 50 dB. Mode resolving results show high-order-mode contents of less than –30 dB in the whole delivery path, resulting in a high-fidelity delivery with M2 factors of 1.20 and 1.23 for the input and output lasers, respectively. Furthermore, the ultimate limits of delivery lengths for solid-core weakly coupled fibers are discussed. This work provides a valuable reference to reconsider the future boom of high-power laser delivery based on solid-core fibers.
High Power Laser Science and Engineering
- Publication Date: Dec. 19, 2024
- Vol. 13, Issue 2, 02000e15 (2025)
Research Articles
Third-harmonic generation via rapid adiabatic passage based on gradient deuterium KDxH2-xPO4 crystalLailin Ji, Li Yin, Jinsheng Liu, Xianghe Guan, Mingxia Xu, Xun Sun, Dong Liu, Hao Xu, Ruijing He, Tianxiong Zhang, Wei Feng, Yong Cui, Xiaohui Zhao, Yanqi Gao, and Zhan Sui
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 (KDxH2-xPO4, 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.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 (KDxH2-xPO4, 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.
High Power Laser Science and Engineering
- Publication Date: Jan. 22, 2025
- Vol. 13, Issue 2, 02000e16 (2025)
Research Articles
High-power high-energy Yb-doped CaGdAlO4 regenerative amplifier with approximately 130 fs pulsesZhengru Guo, Jiangdong Liu, Tingting Liu, Tianjun Yao, Qiang Hao, Heping Zeng, and Edgar Kaksis
We demonstrated a high-power, high-energy regenerative amplifier (RA) based on Yb-doped CaGdAlO4 (Yb:CALGO) crystal, which achieves a maximum average power exceeding 50 W at a repetition rate greater than 50 kHz, and a maximum pulse energy of approximately 7 mJ at a repetition rate of up to 5 kHz. After compression, 130 fs pulses with a peak power of nearly 45 GW are achieved. To the best of our knowledge, this represents the highest average power and pulse energy reported for a Yb:CALGO RA. The RA cavity is specifically designed to maintain excellent stability and output beam quality under a pumping power of 380 W, resulting in a continuous-wave output power exceeding 70 W. For the seeder, a fiber laser utilizing a nonlinear amplification process, which yields a broadband spectrum to support approximately 80 fs pulses, is employed for the high-peak-power pulse generation.We demonstrated a high-power, high-energy regenerative amplifier (RA) based on Yb-doped CaGdAlO4 (Yb:CALGO) crystal, which achieves a maximum average power exceeding 50 W at a repetition rate greater than 50 kHz, and a maximum pulse energy of approximately 7 mJ at a repetition rate of up to 5 kHz. After compression, 130 fs pulses with a peak power of nearly 45 GW are achieved. To the best of our knowledge, this represents the highest average power and pulse energy reported for a Yb:CALGO RA. The RA cavity is specifically designed to maintain excellent stability and output beam quality under a pumping power of 380 W, resulting in a continuous-wave output power exceeding 70 W. For the seeder, a fiber laser utilizing a nonlinear amplification process, which yields a broadband spectrum to support approximately 80 fs pulses, is employed for the high-peak-power pulse generation.
High Power Laser Science and Engineering
- Publication Date: Dec. 23, 2024
- Vol. 13, Issue 2, 02000e17 (2025)
Research Articles
A 5.32 mJ and 47.5 kW cavity-dumped Pr3+:LiYF4 pulsed laser at 639 nmWei Yuan, Shaoqiang Zheng, Zheng Zhang, Yongkang Yao, Huiying Xu, and Zhiping Cai
In this work, we confirm a Pr3+:LiYF4 pulsed laser with high power and high energy at 639 nm based on the acousto-optic cavity dumping technique. The maximum average output power, narrowest pulse width, highest pulse energy and peak power of the pulsed laser at a repetition rate of 0.1 kHz are 532 mW, 112 ns, 5.32 mJ and 47.5 kW, respectively. A 639 nm pulsed laser with such high pulse energy and peak power has not been reported previously. Furthermore, we obtain a widely tunable range of repetition rates from 0.1 to 5000 kHz. The diffracted beam quality factors M2 are 2.18 (in the x direction) and 2.04 (in the y direction). To the best of our knowledge, this is the first time that a cavity-dumped all-solid-state pulsed laser in the visible band has been reported. This work provides a promising method for obtaining high-performance pulsed lasers.In this work, we confirm a Pr3+:LiYF4 pulsed laser with high power and high energy at 639 nm based on the acousto-optic cavity dumping technique. The maximum average output power, narrowest pulse width, highest pulse energy and peak power of the pulsed laser at a repetition rate of 0.1 kHz are 532 mW, 112 ns, 5.32 mJ and 47.5 kW, respectively. A 639 nm pulsed laser with such high pulse energy and peak power has not been reported previously. Furthermore, we obtain a widely tunable range of repetition rates from 0.1 to 5000 kHz. The diffracted beam quality factors M2 are 2.18 (in the x direction) and 2.04 (in the y direction). To the best of our knowledge, this is the first time that a cavity-dumped all-solid-state pulsed laser in the visible band has been reported. This work provides a promising method for obtaining high-performance pulsed lasers.
High Power Laser Science and Engineering
- Publication Date: Jan. 24, 2025
- Vol. 13, Issue 2, 02000e18 (2025)
Research Articles
Deep learning enabled robust wavefront sensing for active beam smoothing with a continuous phase modulatorYamin Zheng, Yifan Zhang, Liquan Guo, Pei Li, Zichao Wang, Yongchen Zhuang, Shibing Lin, Qiao Xue, Deen Wang, and Lei Huang
In laser systems requiring a flat-top distribution of beam intensity, beam smoothing is a critical technology for enhancing laser energy deposition onto the focal spot. The continuous phase modulator (CPM) is a key component in beam smoothing, as it introduces high-frequency continuous phase modulation across the laser beam profile. However, the presence of the CPM makes it challenging to measure and correct the wavefront aberration of the input laser beam effectively, leading to unwanted beam intensity distribution and bringing difficulty to the design of the CPM. To address this issue, we propose a deep learning enabled robust wavefront sensing (DLWS) method to achieve effective wavefront measurement and active aberration correction, thereby facilitating active beam smoothing using the CPM. The experimental results show that the average wavefront reconstruction error of the DLWS method is 0.04 μm in the root mean square, while the Shack–Hartmann wavefront sensor reconstruction error is 0.17 μm.In laser systems requiring a flat-top distribution of beam intensity, beam smoothing is a critical technology for enhancing laser energy deposition onto the focal spot. The continuous phase modulator (CPM) is a key component in beam smoothing, as it introduces high-frequency continuous phase modulation across the laser beam profile. However, the presence of the CPM makes it challenging to measure and correct the wavefront aberration of the input laser beam effectively, leading to unwanted beam intensity distribution and bringing difficulty to the design of the CPM. To address this issue, we propose a deep learning enabled robust wavefront sensing (DLWS) method to achieve effective wavefront measurement and active aberration correction, thereby facilitating active beam smoothing using the CPM. The experimental results show that the average wavefront reconstruction error of the DLWS method is 0.04 μm in the root mean square, while the Shack–Hartmann wavefront sensor reconstruction error is 0.17 μm.
High Power Laser Science and Engineering
- Publication Date: Jan. 22, 2025
- Vol. 13, Issue 2, 02000e19 (2025)
Research Articles
Thermal-lens-free active-mirror ytterbium-doped yttrium aluminum garnet amplifierGrigory Kurnikov, Mikhail Volkov, Anton Gorokhov, Ivan Kuznetsov, Evgeny Perevezentsev, and Ivan Mukhin
A new method is developed for suppressing thermally induced wavefront distortions of the radiation in the active element of disk geometry. The method is based on controlling radial temperature gradients in the active element using a profiled heatsink. An active element with a zero thermal lens developed on the basis of numerical simulation was experimentally demonstrated in a disk laser head. Higher-order phase aberrations in the active element with a profiled heatsink were weaker than in the element with a flat heatsink. Using this method, a thermal-lens-free active-mirror ytterbium-doped yttrium aluminum garnet amplifier with an output energy of 54 mJ at an average pump power of 100 W and a repetition rate of 106 Hz was implemented.A new method is developed for suppressing thermally induced wavefront distortions of the radiation in the active element of disk geometry. The method is based on controlling radial temperature gradients in the active element using a profiled heatsink. An active element with a zero thermal lens developed on the basis of numerical simulation was experimentally demonstrated in a disk laser head. Higher-order phase aberrations in the active element with a profiled heatsink were weaker than in the element with a flat heatsink. Using this method, a thermal-lens-free active-mirror ytterbium-doped yttrium aluminum garnet amplifier with an output energy of 54 mJ at an average pump power of 100 W and a repetition rate of 106 Hz was implemented.
High Power Laser Science and Engineering
- Publication Date: Jan. 14, 2025
- Vol. 13, Issue 2, 02000e20 (2025)
Special Issue on Femtosecond timing and synchronization at large scale facilities (2024)
Submission Open:21 May 2024; Submission Deadline: 15 September 2024
Editor (s): Anne-Laure Calendron, Jungwon Kim, Annika Eichler, Chengcheng Charlie Xu
Special Issue on Relativistic Laser Plasma Interaction (RLPI) Diagnostics and Instrumentation (2022)
Submission Open:1 June 2022; Submission Deadline: 31 December 2022
Editor (s): Joerg Schreiber, Rodrigo Lopez-Martens, Lieselotte Obst-Huebl, Jianhui Bin
Future Control Systems and Machine Learning at High Power Laser Facilities (2022)
Submission Open:1 March 2022; Submission Deadline: 30 October 2022
Editor (s): Andreas Döpp, Matthew Streeter, Scott Feister, Hyung Taek Kim, Charlotte Palmer
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Post-compression of the GW-level femtosecond pulse in a solid-state multi-pass cell
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Metrology for sub-Rayleigh-length target positioning in ∼1022 W/cm2 laser–plasma experiments
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Random pinhole attenuator for high-power laser beamsOn the Cover
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The Linac Coherent Light Source II photoinjector laser infrastructureOn the Cover
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