中红外波段高功率激光光源在工业加工和生物医疗等领域中有着广泛的应用。报道了基于主振荡器功率放大器（MOPA）结构的百瓦级中红外连续波光纤随机激光器，获得了最高输出功率为100.40 W、斜率效率为47.8%、波长为1980 nm的连续波激光输出。得益于MOPA结构中光纤随机激光种子源在激光放大过程中的光谱带宽保持特性，100.40 W激光输出时的3 dB光谱带宽仅为～0.2 nm。激光器的短时时域强度波动和长时功率波动均表现出优良的稳定性。所提实验技术方案和实验结果有望进一步拓宽中红外高功率光纤随机激光器的应用范围。

1.7 μm激光处于眼安全波段并位于许多重要气体分子的指纹吸收峰，在生物医疗、气体传感等领域具有重要应用价值。而涡旋光束作为一种新兴的结构光场，其具有环形光强分布和螺旋相位波前，并携带轨道角动量，在光通信、微粒操控等领域应用广泛。因此发展1.7 μm高能涡旋激光器具有重要的研究价值和应用前景。但传统稀土离子掺杂光纤或晶体的发射谱，或难以覆盖该波段，或在该波段激光增益较小，且涡旋光产生主要基于空间光结构，导致1.7 μm波段涡旋光激光系统复杂、集成度低，难以实现高功率输出。本文利用螺旋长周期光纤光栅作为涡旋模式转换器，在基于受激拉曼散射效应的1.7 μm波段光纤随机激光半开放腔中实现了全光纤结构的高功率涡旋激光输出，最大输出功率为2.09 W，中心波长为1690 nm。得益于涡旋光纤随机激光器的全光纤结构，该装置具有良好的时域稳定性，短时时域波动低至2.8%。该研究结果不仅为实现兼具高功率输出和良好时域稳定性的紧凑型1.7 μm波段涡旋激光器提供有效方案，还能进一步拓展其在激光医疗、气体检测、光镊和生物成像等领域的应用。

报道了一种1.85 μm亚纳秒脉宽的Tm∶GdVO₄被动锁模激光器。通过使用商用半导体可饱和吸收镜（SESAM）和高透过率的输出耦合镜（OCs），实现了Tm∶GdVO₄短波段、亚纳秒脉宽的激光输出。对于连续波（CW）运转，当使用透过率分别为10%、20%和30%的不同OCs时，激光输出功率均超过1 W，在1844、1850、1851、1861、1865 nm波长上分别产生了激光振荡。对于连续波锁模（CWML）运转，通过使用上述不同OCs，均实现了稳定的输出，工作波长均位于1851.6 nm附近，光谱宽度始终不高于光谱仪0.05 nm的分辨率，输出脉宽分别为474、752、651 ps。其中，当使用透过率为30%的OC时，可实现320 mW的最大平均输出功率。

《中国激光》创刊出版逾500期，值此喜庆时刻，编辑部特别制作了“中国激光大科学装置”专题，奉献给广大读者和激光科技工作者。大科学装置是建立具备强大国际竞争力的大型科研基地的重要条件，也是现代科学技术诸多领域取得突破的必要条件，对科技发展具有重要的里程碑式意义。

神光Ⅱ大型固体高功率激光装置是我国激光驱动器发展历史的里程碑, 其成功研制使我国高功率固体激光工程与技术、聚变物理与基础物理研究实现了全面且本质的跨越式发展。简要概述了神光Ⅱ激光装置研制中创新发展的大量工程方案与技术手段, 举例介绍了神光Ⅱ激光装置在近20年来的高质量运行中取得的众多有国际影响力的研究成果。经多方支持和多年持续发展, 已经形成数万焦耳级纳秒激光装置、皮秒拍瓦以及飞秒拍瓦激光装置等, 这些装置是我国惯性约束核聚变、强场物理、高能量密度物理等研究领域中重要的物理实验核心平台之一。

超表面在柱矢量光束(CVB)产生方面具有效率高、器件精巧等优势,被广泛用于CVB产生及相关应用,但是该方法存在一个比较大的缺点:超表面的结构是固定的,因此生成的CVB的阶数是不可调的。为了解决该问题,在1550 nm波段实验证明了一种通过模式的加减操作来高效调控CVB偏振阶数的方法。通过将两块超表面级联在一起,实现了CVB偏振阶数的减法运算;在两块超表面之间插入一块半波片,通过反转CVB偏振阶数,实现了CVB偏振阶数的加法运算。最终实现了在-8~8范围内以2为步长的CVB偏振阶数调控操作,实验结果与Jones矩阵的计算结果完全吻合。

Large aperture high-power laser drivers usually focus the high power laser beams in 2×2 quads to the target chamber center in order to increase the light intensity on the target plane. The large aperture wedged focus lenses are the core components in the focus system of quadruplets of beams, and it is thought possible to use four two-dimensional off-axis wedged focus lenses as four sub-lenses to make up a larger aperture wedged focus lens in form to focus the four beams. Given that the large aperture two-dimensional off-axis wedged focus lenses are processed and used difficultly, the wedged focus lenses are divided into three categories: the two-dimensional off-axis wedged focus lenses, the onedimensional off-axis wedged focus lenses, and the non-off-axis wedged focus lenses. On the basis of the three modes of the wedged focus lenses and the corresponding specific incidence angles of each sub-beam, the three focus schemes for the 2×2 beam array are put forward to comparatively research the light intensity distribution on the target plane. Research results show that from a perspective of the coherence among the four sub-beams, the phase factors of each sub-beam respectively introducing by the three focus systems with the two-dimensional off-axis, one-dimensional off-axis, and non-off-axis wedged focus lenses are asymmetric, asymmetric and symmetric inside each sub-beam, and symmetric, asymmetric and symmetric among the four sub-beams. Therefore, the wave front consistency of the four sub-beams decreases in the order of the focus systems with the non-off-axis, two-dimensional off-axis, and one-dimensional off-axis wedged focus lenses. The focus schemes with the non-off-axis wedged focus lenses for 2×2 beam array can get the narrowest main-lobe, the strongest peak-value intensity, the highest energy concentration ratio on the target plane, followed by the one-dimensional off-axis and two-dimensional off-axis wedged focus lenses. The off-axis mode of the wedged focus lenses not only increases the complexity in the course of processing and using, but also increases the main-lobe size, decreases the peak-value intensity and the energy concentration ratio, which obtains a weaker focusing characteristics than that of the non-off-axis mode of the wedged focus lenses. Research results can provide an important reference for the design of the focus system in the target area of high-power laser drivers.

Based on the optical transmission theory, the reason why front-surface particle contamination may induce the original damage of thin optical components is considered, and a damage mechanism is put forward: The localized thermal deformation of an optical element induced by the thermal effect of particle contamination together with the shading effect of it can disturb the laser beams. Simulated results show that for a high power laser, the localized thermal deformation of thin optical components, which disturbs the laser beam, is an important cause to produce strong light intensity modulations. The surface shape, phase delay, and thermal diffusion length of a localized thermal deformation are constantly changing with the increase of laser pulse shot number, so the highest light intensity modulation will be produced at different positions in the thickness direction or the xy direction on the rear-surface of an optical element. This not only can easily induce some damages on the rear-surface of the optical element, but also cause the interior damages scattered in the thickness direction.

实验研究了圆孔衍射调制下的强激光在克尔非线性介质中的传输特性。观测了小尺度自聚焦效应引起的多细丝形成、单根细丝演化以及细丝之间相互作用过程。结果表明： 在非线性传输过程中，衍射调制光束在空间特定位置出现调制增长，导致光束分裂形成多路细丝；单根细丝的强度并非无限增长，而是达到一定值后通过锥形发射释放多余能量，同时与背景光相互作用形成新细丝；相距较近的细丝之间通过干涉相互作用，使其在附近区域形成新的细丝。