Journals >High Power Laser Science and Engineering
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2025
Volume: 13 Issue 2
15 Article(s)
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Research Articles
Ultrafast characterization of plasma critical surface evolution in inertial confinement fusion experiments with chirped laser pulses
Linjun 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 reflecLaser-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)
An investigation of the emittance of escaping fast electron beams from planar and nanowire targets
E. 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. NanowFast 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)
High-fidelity delivery of kilowatt-level single-mode lasers through a tapered multimode fiber over one hundred meters
Xiao 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, guidesThe 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)
Third-harmonic generation via rapid adiabatic passage based on gradient deuterium KDxH2-xPO4 crystal
Lailin 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 deuteBroadband 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)
High-power high-energy Yb-doped CaGdAlO4 regenerative amplifier with approximately 130 fs pulses
Zhengru 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, 13We 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)
A 5.32 mJ and 47.5 kW cavity-dumped Pr3+:LiYF4 pulsed laser at 639 nm
Wei 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 aIn 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)
Deep learning enabled robust wavefront sensing for active beam smoothing with a continuous phase modulator
Yamin 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 laserIn 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)
Thermal-lens-free active-mirror ytterbium-doped yttrium aluminum garnet amplifier
Grigory 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 ofA 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)
Focal spot polarization distribution under polarization smoothing
Yanghui Tang, Shenlei Zhou, Shouying Xu, and Cheng Liu
Polarization smoothing can effectively improve the uniformity of focal spots. In this study, we theoretically and experimentally investigated the polarization synthesis of the focal spot under a birefringent wedge (BW) and speckle under the coupling of the BW and continuous phase plate. Polarization distribution was exPolarization smoothing can effectively improve the uniformity of focal spots. In this study, we theoretically and experimentally investigated the polarization synthesis of the focal spot under a birefringent wedge (BW) and speckle under the coupling of the BW and continuous phase plate. Polarization distribution was experimentally obtained using rotating quarter-wave plate measurement under a specific wedge angle. The simulated and experimental results are consistent, demonstrating that the focal spot is in a state of coexistence of elliptical and linear polarizations. In addition, the polarization state is determined by the ratio of the amplitudes and the phase difference between the sub-beams. The simulation results showed that the proportion of linear polarization increased with the separation angle of the sub-beam. In contrast, it decreased with the incident light aperture. This research is crucial for accurately describing the polarization distribution and further understanding the laser–plasma interactions..
High Power Laser Science and Engineering
- Publication Date: Jan. 21, 2025
- Vol. 13, Issue 2, 02000e21 (2025)
X-ray speckle reduction using a high-speed piezoelectric deformable mirror system
Shuai Yan, Hui Jiang, Zhisen Jiang, Dongxu Liang, Jianan Xie, Hai Zhu, Guoyang Shu, Ningyu Ben, and Aiguo Li
An advanced deformable Kirkpatrick–Baez (K-B) mirror system was developed, equipped with high-speed piezoelectric actuators, and designed to induce beam decoherence and significantly enhance the quality of X-ray imaging by minimizing undesirable speckles in synchrotron radiation or free-electron laser facilities. Each An advanced deformable Kirkpatrick–Baez (K-B) mirror system was developed, equipped with high-speed piezoelectric actuators, and designed to induce beam decoherence and significantly enhance the quality of X-ray imaging by minimizing undesirable speckles in synchrotron radiation or free-electron laser facilities. Each individual mirror is engineered with 36 independent piezoelectric actuators that operate in a randomized manner, orchestrating the mirror surface to oscillate at a high frequency up to 100 kHz. Through in situ imaging single-slit diffraction measurement, it has been demonstrated that this high-frequency-vibration mirror system is pivotal in disrupting the coherent nature, thereby diminishing speckle formation. The impact of the K-B mirror system is profound, with the capability to reduce the image contrast to as low as 0.04, signifying a substantial reduction in speckle visibility. Moreover, the coherence of the X-ray beam is significantly lowered from an initial value exceeding 80% to 13%..
High Power Laser Science and Engineering
- Publication Date: Jan. 17, 2025
- Vol. 13, Issue 2, 02000e22 (2025)
High-power microsecond ultraviolet burst-mode pulse laser with a rectangular envelope and GHz-adjustable intra-burst pulses
Yanran Gu, Xinyue Niu, Fuyin Liu, Ting He, Jinmei Yao, Muyu Yi, Langning Wang, Tao Xun, and Jinliang Liu
We demonstrate a high-peak-power master oscillator power amplifier burst-mode laser system that generates microsecond burst duration pulses at 355 nm with a GHz-adjustable intra-burst pulse frequency. In the fiber seed, a high-bandwidth electro-optic modulator is employed to modulate a continuous-wave (CW) laser into aWe demonstrate a high-peak-power master oscillator power amplifier burst-mode laser system that generates microsecond burst duration pulses at 355 nm with a GHz-adjustable intra-burst pulse frequency. In the fiber seed, a high-bandwidth electro-optic modulator is employed to modulate a continuous-wave (CW) laser into a pulse train at GHz frequency. To acquire a microsecond rectangular burst pulse envelope, two acousto-optic modulators are used to chop the CW pulse train and generate a pre-compensation burst envelope. A three-stage neodymium-doped yttrium aluminum garnet amplifier boosts the burst-mode fiber seed’s burst energy of 1.65 J at 1064 nm. To achieve a high-power ultraviolet (UV) burst-mode laser, sum frequency generation in a LiB3O5 crystal is employed to convert the wavelength, achieving over 300 kW of peak power at 1.15 μs/10 Hz. The intra-burst pulse frequency of the UV burst laser can be adjustable from 1 to 10 GHz with a sinusoidal waveform. To the best of our knowledge, this paper represents the highest reported microsecond UV burst-mode laser in terms of output energy and peak power with the GHz-adjustable intra-burst frequency. The high-power microsecond UV burst-mode pulse laser can be directly used as a light-driven source in large-bandwidth/high-power microwave photonic systems, providing a long pulse width and high peak power laser while significantly improving the system’s multi-parameter adjustment capability and adaptability..
High Power Laser Science and Engineering
- Publication Date: Jan. 24, 2025
- Vol. 13, Issue 2, 02000e23 (2025)
Effects of X-ray pre-ablation on the implosion process for double-cone ignition
Bihao Xu, Xiaohu Yang, Ze Li, Bo Zeng, Zehao Chen, Lingrui Li, Ye Cui, Guobo Zhang, Yanyun Ma, and Jie Zhang
The double-cone ignition scheme is a promising novel ignition method, which is expected to greatly save the driver energy and enhance the robustness of the implosion process. In this paper, ablation of the inner surface of the cone by the hard X-ray from coronal Au plasma is studied via radiation hydrodynamics simulatiThe double-cone ignition scheme is a promising novel ignition method, which is expected to greatly save the driver energy and enhance the robustness of the implosion process. In this paper, ablation of the inner surface of the cone by the hard X-ray from coronal Au plasma is studied via radiation hydrodynamics simulations. It is found that the X-ray ablation of the inner wall will form strong pre-plasma, which will significantly affect the implosion process and cause the Au plasma to mix with the fuel, leading to ignition failure. The radiation and pre-ablation intensities in the system are estimated, and the evolutions of areal density, ion temperature and the distribution of Au ions are analysed. In addition, the mixing of Au in CH at collision is quantified. Then, a scheme to reduce the X-ray pre-ablation by replacing the gold cone with a tungsten cone is proposed, showing that it is effective in reducing high-Z mixing and improving collision results..
High Power Laser Science and Engineering
- Publication Date: Jan. 16, 2025
- Vol. 13, Issue 2, 02000e24 (2025)
High-power, widely wavelength-tunable, single-frequency pulsed fiber master oscillator power amplifier at 2.8 μm
Zongxiao Fan, Wenshu Liu, Zhehao Wu, Shengyi Wang, Huimin Yue, Chen Wei, and Yong Liu
We present a high-power mid-infrared single-frequency pulsed fiber laser (SFPFL) with a tunable wavelength range from 2712.3 to 2793.2 nm. The single-frequency operation is achieved through a compound cavity design that incorporates a germanium etalon and a diffraction grating, resulting in an exceptionally narrow seedWe present a high-power mid-infrared single-frequency pulsed fiber laser (SFPFL) with a tunable wavelength range from 2712.3 to 2793.2 nm. The single-frequency operation is achieved through a compound cavity design that incorporates a germanium etalon and a diffraction grating, resulting in an exceptionally narrow seed linewidth of approximately 780 kHz. Employing a master oscillator power amplifier configuration, we attain a maximum average output power of 2.6 W at 2789.4 nm, with a pulse repetition rate of 173 kHz, a pulse energy of 15 μJ and a narrow linewidth of approximately 850 kHz. This achievement underscores the potential of the mid-infrared SFPFL system for applications requiring high coherence and high power, such as high-resolution molecular spectroscopy, precision chemical identification and nonlinear frequency conversion..
High Power Laser Science and Engineering
- Publication Date: May. 13, 2025
- Vol. 13, Issue 2, 02000e26 (2025)
Spatial characterization of debris ejection from the interaction of a tightly focused PW-laser pulse with metal targets
I.-M. Vladisavlevici, C. Vlachos, J.-L. Dubois, D. Haddock, S. Astbury, A. Huerta, S. Agarwal, H. Ahmed, J. I. Apiñaniz, M. Cernaianu, M. Gugiu, M. Krupka, R. Lera, A. Morabito, D. Sangwan, D. Ursescu, A. Curcio, N. Fefeu, J. A. Pérez-Hernández, T. Vacek, P. Vicente, N. Woolsey, G. Gatti, M. D. Rodríguez-Frías, J. J. Santos, P. W. Bradford, and M. Ehret
We present a novel scheme for rapid quantitative analysis of debris generated during experiments with solid targets following relativistic laser–plasma interaction at high-power laser facilities. Results are supported by standard analysis techniques. Experimental data indicate that predictions by available mo
We present a novel scheme for rapid quantitative analysis of debris generated during experiments with solid targets following relativistic laser–plasma interaction at high-power laser facilities. Results are supported by standard analysis techniques. Experimental data indicate that predictions by available modelling for non-mass-limited targets are reasonable, with debris of the order of hundreds of μg per shot. We detect for the first time two clearly distinct types of debris emitted from the same interaction. A fraction of the debris is ejected directionally, following the target normal (rear and interaction side). The directional debris ejection towards the interaction side is larger than on the side of the target rear. The second type of debris is characterized by a more spherically uniform ejection, albeit with a small asymmetry that favours ejection towards the target rear side.
.High Power Laser Science and Engineering
- Publication Date: Feb. 03, 2025
- Vol. 13, Issue 2, 01000e27 (2025)
Computational near-field and far-field parameter measurement of high-power lasers using modified coherent modulation imaging
Hua Tao, Xiaoliang He, Chengcheng Chang, Liqing Wu, Deng Liu, Fei Chen, Cheng Liu, and Jianqiang Zhu
Accurate characterization of high-power laser parameters, especially the near-field and far-field distributions, is crucial for inertial confinement fusion experiments. In this paper, we propose a method for computationally reconstructing the complex amplitude of high-power laser beams using modified coherent modulatio
Accurate characterization of high-power laser parameters, especially the near-field and far-field distributions, is crucial for inertial confinement fusion experiments. In this paper, we propose a method for computationally reconstructing the complex amplitude of high-power laser beams using modified coherent modulation imaging. This method has the advantage of being able to simultaneously calculate both the near-field (intensity and wavefront/phase) and far-field (focal-spot) distributions using the reconstructed complex amplitude. More importantly, the focal-spot distributions at different focal planes can also be calculated. To verify the feasibility, the complex amplitude optical field of the high-power pulsed laser was measured after static aberrations calibration. Experimental results also indicate that the near-field wavefront resolution of this method is higher than that of the Hartmann measurement. In addition, the far-field focal spot exhibits a higher dynamic range (176 dB) than that of traditional direct imaging (62 dB).
.High Power Laser Science and Engineering
- Publication Date: Feb. 20, 2025
- Vol. 13, Issue 2, 01000e28 (2025)
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