针对高能激光器出光过程中出现的大量离焦和0°像散低阶像差现象，提出了基于哈特曼波前传感器和二维整形光路的XY离焦像差校正方法。首先，通过对Zernike多项式的离焦项和0°像散项进行线性组合得到XY离焦像差的表达式，该XY离焦像差系数的大小可直接表征X离焦和Y离焦的波前PV值。同时，通过微调高能激光器中二维整形光路中的镜子间距，可实现激光器输出光束XY离焦波面的补偿。因此，首先利用哈特曼波前传感器提取出光束的XY离焦像差系数大小，而后再根据XY离焦像差系数的大小实时闭环微调二维整形光路中的镜子间距，从而实现XY离焦像差的校正，改善输出光束的光束质量。实验结果表明，该方法可有效地将高能激光器输出光束XY离焦量的PV值由5.2 μm和1.1 μm校正到0.5 μm以下，相应的光束质量β因子由3.1降到1.8，光束质量得到明显改善。

高能激光器性能直接决定了激光定向能的毁伤能力和打击射程，为此美国相继启动多项计划，以研制出高功率、高效、紧凑、轻量化，用于战场的坚固型激光器。2019年，启动了激光器定标放大计划（high energy laser scaling initiative，HELSI），制定出最新的国家级激光放大路线图。首先介绍美国HELSI计划的启动背景、研究内容和实施阶段，其次分析HELSI计划第一阶段300 kW的研究进展，最后评述HELSI计划进展的后续影响。综合分析可知，目前洛·马公司的光谱合成光纤激光器技术在第一阶段率先胜出，不仅获得陆军300 kW作战光源的订单，而且还首先获得HELSI计划第二阶段500 kW的研制合同；HELSI计划的进展，使导弹防御局（missile defense agency，MDA）重新重视用于拦截助推段弹道导弹的定向能**；HELSI计划支持了4种技术路线进行竞争发展，不过未来何种技术路线会最终胜出并部署在战场上，还需要加强先期论证，突破“技术迷雾”。

The recent achievement of fusion ignition with laser-driven technologies at the National Ignition Facility sets a historic accomplishment in fusion energy research. This accomplishment paves the way for using laser inertial fusion as a viable approach for future energy production. Europe has a unique opportunity to empower research in this field internationally, and the scientific community is eager to engage in this journey. We propose establishing a European programme on inertial-fusion energy with the mission to demonstrate laser-driven ignition in the direct-drive scheme and to develop pathway technologies for the commercial fusion reactor. The proposed roadmap is based on four complementary axes: (i) the physics of laser–plasma interaction and burning plasmas; (ii) high-energy high repetition rate laser technology; (iii) fusion reactor technology and materials; and (iv) reinforcement of the laser fusion community by international education and training programmes. We foresee collaboration with universities, research centres and industry and establishing joint activities with the private sector involved in laser fusion. This project aims to stimulate a broad range of high-profile industrial developments in laser, plasma and radiation technologies along with the expected high-level socio-economic impact.

A fully automatic fail-safe beam shaping system based on a liquid crystal on a silicon spatial light modulator has been implemented in the high-energy kilowatt-average-power nanosecond laser system Bivoj. The shaping system corrects for gain nonuniformity and wavefront aberrations of the front-end of the system. The beam intensity profile and the wavefront at the output of the front-end were successfully improved by shaping. The beam homogeneity defined by the beam quality parameters was improved two to three times. The root-mean-square value of the wavefront was improved more than 10 times. Consequently, the shaped beam from the second preamplifier led to improvement of the beam profile at the output of the first main cryo-amplifier. The shaping system is also capable of creating nonordinary beam shapes, imprinting cross-references into the beam, or masking certain parts of the beam.

Since the first laser was invented, the pursuit of high-energy lasers (HELs) has always been enthusiastic. The first revolution of HELs was pushed by the fusion of laser and aerospace in the 1960s, with the chemical rocket engines giving fresh impetus to the birth of gas flow and chemical lasers, which finally turned megawatt lasers from dream into reality. Nowadays, the development of HELs has entered the age of electricity as well as the rocket engines. The properties of current electric rocket engines are highly consistent with HELs’ goals, including electrical driving, effective heat dissipation, little medium consumption and extremely light weight and size, which inspired a second fusion of laser and aerospace and motivated the exploration for potential HELs. As an exploratory attempt, a new configuration of diode pumped metastable rare gas laser was demonstrated, with the gain generator resembling an electric rocket-engine for improved power scaling ability.

We present a high-energy, hundred-picosecond (ps) pulsed mid-ultraviolet solid-state laser at 266 nm by a direct second harmonic generation (SHG) in a barium borate (BaB₂O₄, BBO) nonlinear crystal. The green pump source is a 710 mJ, 330 ps pulsed laser at a wavelength of 532 nm with a repetition rate of 1 Hz. Under a green pump energy of 710 mJ, a maximum output energy of 253.3 mJ at 266 nm is achieved with 250 ps pulse duration resulting in a peak power of more than 1 GW, corresponding to an SHG conversion efficiency of 35.7% from 532 to 266 nm. The experimental data were well consistent with the theoretical prediction. To the best of our knowledge, this laser exhibits both the highest output energy and highest peak power ever achieved in a hundred-ps/ps regime at 266 nm for BBO-SHG.